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Residents of the Imperial Valley, a rural, agricultural border region in California, have raised concerns over high rates of pediatric asthma symptoms. There is an urgent need to understand the influences and predictors of children’s respiratory health in Imperial Valley. We assessed the impacts of sociodemographic, lifestyle, and household factors on children’s respiratory health and asthma prevalence by administering a survey to parents of elementary school children (n = 357) in northern Imperial Valley. We observed an overall asthma prevalence of 22.4% and respiratory symptoms and allergies were widely reported, including wheezing (35.3%), allergies (36.1%), bronchitic symptoms (28.6%), and dry cough (33.3%). Asthmatics were significantly more likely to report respiratory symptoms, but high rates of wheezing, allergies, and dry cough were observed among nonasthmatics, suggesting the possibility for underdiagnosis of respiratory impairment in our school-age population. Having an asthmatic mother and exposure to environmental tobacco smoke were also associated with greater odds of asthma. Our findings provide evidence to support community concerns about children’s respiratory health, while also suggesting that household and demographic characteristics have limited explanatory power for assessing asthma in this population. This work provides critical baseline data with which to evaluate local environmental factors and their influence on asthma and respiratory symptoms.
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International Journal of
Environmental Research
and Public Health
Article
Assessment of Respiratory Health Symptoms and
Asthma in Children near a Drying Saline Lake
Shohreh F. Farzan 1,*, Mitiasoa Razafy 1, Sandrah P. Eckel 1, Luis Olmedo 2, Esther Bejarano 2and
Jill E. Johnston 1
1Department of Preventive Medicine, Keck School of Medicine of University of Southern California,
2001 N. Soto Street, MC 9237, Los Angeles, CA 90089, USA; razafy@usc.edu (M.R.); eckel@usc.edu (S.P.E.);
jillj@usc.edu (J.E.J.)
2Comite Civico del Valle, Brawley, CA 92227, USA; luis@ccvhealth.org (L.O.); esther@ccvhealth.org (E.B.)
*Correspondence: sarzan@usc.edu; Tel.: +1-323-442-5101
Received: 20 September 2019; Accepted: 9 October 2019; Published: 11 October 2019


Abstract:
Residents of the Imperial Valley, a rural, agricultural border region in California, have raised
concerns over high rates of pediatric asthma symptoms. There is an urgent need to understand the
influences and predictors of children’s respiratory health in Imperial Valley. We assessed the impacts
of sociodemographic, lifestyle, and household factors on children’s respiratory health and asthma
prevalence by administering a survey to parents of elementary school children (n=357) in northern
Imperial Valley. We observed an overall asthma prevalence of 22.4% and respiratory symptoms and
allergies were widely reported, including wheezing (35.3%), allergies (36.1%), bronchitic symptoms
(28.6%), and dry cough (33.3%). Asthmatics were significantly more likely to report respiratory
symptoms, but high rates of wheezing, allergies, and dry cough were observed among nonasthmatics,
suggesting the possibility for underdiagnosis of respiratory impairment in our school-age population.
Having an asthmatic mother and exposure to environmental tobacco smoke were also associated
with greater odds of asthma. Our findings provide evidence to support community concerns about
children’s respiratory health, while also suggesting that household and demographic characteristics
have limited explanatory power for assessing asthma in this population. This work provides critical
baseline data with which to evaluate local environmental factors and their influence on asthma and
respiratory symptoms.
Keywords:
asthma; children’s respiratory health; rural areas; Imperial County,
California; environment
1. Introduction
Over six million children in the United States (USA) are living with asthma, making it the most
commonly diagnosed chronic childhood disorder [
1
]. In 2015, the reported prevalence of asthma
among U.S. children was 8.4%, with rates ranging up to 13.4% among minority populations [
1
].
Although children of Mexican heritage have an overall lower prevalence of asthma compared to other
groups of U.S. children, recent trends further suggest widening racial, ethnic, and economic disparities
in terms of pediatric asthma prevalence, which may be in part related to environmental factors [
2
6
].
For example, the pediatric asthma prevalence observed among USA–Mexico border populations is
frequently much higher than the national average of 8% for Hispanic children, although the reasons
for these population dierences remain largely unknown [7].
There is limited research on the prevalence of asthma and related risk factors in predominately
Mexican-American rural communities in the USA. One such community in the rural agricultural
valley situated between the USA–Mexico border and a drying saline lake in southeastern California
Int. J. Environ. Res. Public Health 2019,16, 3828; doi:10.3390/ijerph16203828 www.mdpi.com/journal/ijerph
Int. J. Environ. Res. Public Health 2019,16, 3828 2 of 15
(CA) has raised concern over elevated rates of pediatric asthma symptoms in their region. In this
primarily low-income, majority Mexican-American region known as the Imperial Valley, the rate of
asthma-related emergency room visits and hospitalizations for children ages 0–17 years is double the
CA state average [
8
]. In 2005, a CA Health Department-led study in the region observed an asthma
prevalence of 20% among middle school students and high rates of respiratory symptoms among
nonasthmatics, suggesting that undiagnosed asthma was potentially common [
8
]. To date, the factors
contributing to the high rates of adverse childhood respiratory health conditions in Imperial Valley
have not been explored.
To begin to assess the factors influencing respiratory health in this unique population, we evaluated
the current prevalence of asthma and other respiratory health conditions among elementary school
children living in the northern Imperial Valley, CA. We further sought to determine whether asthma
prevalence rates varied across sociodemographic and household characteristics. We focused on the
northern end of the valley, in response to concerns regarding changing weather patterns, droughts,
and competing water demands that are poised to cause the rapid shrinking of the Salton Sea,
a 350-square-mile land-locked saline “sea” with the potential to significantly impact the future
respiratory health and quality of life for nearby residents [
9
12
]. The recent enactment of a federally
mandated water transfer agreement at the end of 2018 reduced the allotment of Colorado River water
for the Imperial Valley, diverting water resources to nearby urban regions and eectively ending
the supply of water to the Salton Sea [
13
]. This reallocation of water resources has resulted in an
increasingly retreating shoreline leaving behind exposed playa, which has the potential to generate
wind-blown dust, adding to ongoing community concerns about the already poor local air quality
from contributors such as agricultural burning practices and cross-border particulate matter sources.
The drying of the Salton Sea has unknown public health implications and the existing vulnerabilities of
nearby populations are largely unmeasured. Characterizing the current respiratory health risk factors
in this population could inform public health protection in the face of changing environmental factors.
2. Methods
The Imperial Valley, located along the USA–Mexico border in Imperial County, CA, primarily
consists of agricultural fields and open, undeveloped desert land, populated by a handful of small cities
and towns [
14
,
15
]. Imperial County is considered a rural medical service study area (MSSA), defined
as an area with fewer than 250 persons per square mile and no population center exceeding 50,000,
and parts of northern Imperial County are defined as a frontier MSSA, indicating a rural MSSA with
fewer than 11 residents per square mile [
16
,
17
]. A cross-sectional school-based study was conducted
between May 2017 and May 2018 in Imperial County, CA. Four elementary schools across four towns
within approximately 20 miles of the Salton Sea were invited to participate. In three of the four towns,
a single elementary school services the entire town; in the fourth town, a representative elementary
school was selected with input from community partners. Study stavisited classrooms to introduce
the study to the children and distribute the study packets. All surveys, materials, and consent forms
were provided in both English and Spanish, and children returned all study materials to the classroom
within one week. Parents and guardians completed a 64-item health survey, adapted from validated
questionnaires from the International Study of Asthma and Allergies in Childhood (ISAAC) [
18
],
a questionnaire developed to assess asthma prevalence that has been validated in populations around
the world, as well as questions used as part of the Southern California Children’s Health Study [19].
Demographic and lifestyle questions assessed the children’s characteristics such as age, sex,
race/ethnicity, as well as parent/caregiver information including annual household income, educational
attainment, insurance coverage, and tobacco usage. Questions on the child’s medical and health history
focused on the occurrence of severe respiratory illnesses before the age of two, asthma diagnoses,
and recent respiratory conditions and symptoms. Respiratory medication use was assessed using
photographic charts of common asthma rescue and controller medications. Questions about the home
environment included the presence of pets or farm animals, as well as indoor housing conditions
Int. J. Environ. Res. Public Health 2019,16, 3828 3 of 15
(presence of mold, carpeting, water damage, pests, home heating and cooling, humidifier use, and gas
stove use).
Health surveys were distributed to 429 children during two week-long distribution periods over
the data collection year between May 2017 and May 2018, with an overall participation rate of 83.2%
(357 of 429). For the purposes of this study, if a survey was filled out for a child during both rounds of
data collection, the first survey was used in these analyses. Written informed consent was obtained
from a parent or guardian. All protocols, consent forms, and survey materials were approved by the
University of Southern California Institutional Review Board (HS-17-00204).
Statistical Analysis
All analyses were conducted using STATA IC Version 15 (Stata, College Station, TX, USA).
Chi-square tests were used to test for associations between categorical variables. Logistic regression
was used to examine associations between potential risk factors and binary outcome variables
(physician-diagnosed asthma or the presence of respiratory symptoms). We examined the associations
in unadjusted models and stepwise adjustment for a priori selected covariates (minimally adjusted
model: age and sex, language of survey response) and fully-adjusted final models (adjusted for age,
sex, language of survey response, education level of the parent/caregiver survey respondent, school of
enrollment). Statistical significance was defined as p<0.05.
Children were classified as asthmatic if the child’s parent answered armatively to the question
“Has your child ever received an ocial doctor’s diagnosis for asthma?” A child was considered to
have bronchitic symptoms if the child’s parent reported at least one of the following: 1) daily cough for
three months in a row, 2) congestion or phlegm for at least three months in a row, or 3) bronchitis in the
past year [
20
]. Health insurance was categorized into public, private, or none. Respiratory medications
were categorized as rescue, control, or other [21].
3. Results
A total of 357 students participated in this study (Table 1). The mean age was 7.6 (SD: 0.86) years.
Our sample included slightly more female (54.9%) than male children (45.1%). Most parents completed
the questionnaires in English (64.2%), with almost all participants self-identifying as Latino/a (93.3%).
Most reported having health insurance (90.5%), with the majority enrolled in a public health insurance
plan (70.3%). Approximately one-third of participants reported a total household of less than $15,000
a year (30.0%), with a minority of participants earning above $50,000 (14.3%). Approximately 20%
of the study population did not know or chose not to report their annual total household income.
Of the parents or caregivers who responded to the questionnaire, approximately 68% were the child’s
biological mother, 19% were the child’s biological father, and the remaining 13% were other relatives
or caregivers. About half of the parent or caregiver respondents had a high school education or less
(50.4%).
Int. J. Environ. Res. Public Health 2019,16, 3828 4 of 15
Table 1. Demographic characteristics of asthmatic and nonasthmatic study participants (N=357).
Demographic Characteristics All
N=357 (%)
Asthmatics
N=80 (%)
Nonasthmatics
N=277 (%) p-Value a
Language of survey
English 229 (64.2) 59 (73.8) 170 (61.4) 0.04
Spanish 128 (35.8) 21 (26.3) 107 (38.6)
Sex
Female 196 (54.9) 41 (51.3) 155 (56.0) 0.46
Male 161 (45.1) 39 (48.8) 122 (44.0)
Race/Ethnicity
Latino 333 (93.3) 74 (92.5) 259 (93.5) 0.38
White 18 (5.0) 5 (6.3) 13 (4.7)
Black 3 (0.8) 0 (0.0) 3 (1.1)
Native American 1 (0.3) 1 (1.3) 0 (0.0)
Other 2 (0.6) 0 (0.0) 2 (0.7)
Age
5–6 years 32 (9.0) 9 (11.3) 23 (8.3) 0.69
7 years 131 (36.7) 28 (35.0) 103 (37.2)
8 years 148 (41.5) 35 (43.8) 113 (40.8)
9–10 years 46 (12.9) 8 (10.0) 38 (13.7)
Health Insurance
Public 251 (70.3) 51 (63.8) 200 (72.2) 0.01
Private 72 (20.2) 25 (31.3) 47 (17.0)
None 34 (9.5) 4 (5.0) 30 (10.8)
Total Household Income
Less than $15,000 107 (30.0) 22 (27.5) 85 (30.7) 0.01
$15,000 to $29,999 71 (19.9) 15 (18.8) 56 (20.2)
$30,000 to $49,999 54 (15.1) 8 (10.0) 46 (16.6)
More than $50,000 51 (14.3) 21 (26.3) 30 (10.8)
Don’t know 74 (20.7) 14 (17.5) 60 (21.7)
Parent/caregiver education b
Less than 12th grade 90 (25.2) 13 (16.3) 77 (27.8) 0.08
Completed 12th grade 90 (25.2) 23 (28.8) 67 (24.2)
Some college or technical school 122 (34.2) 30 (37.5) 92 (33.2)
4 years of college or more 35 (9.8) 12 (15.0) 23 (8.3)
Missing 20 (5.6) 2 (2.5) 18 (6.5)
Two-adult household
Yes 202 (56.6) 46 (57.5) 156 (56.3) 0.50
No 142 (39.8) 34 (42.5) 108 (39.0)
Missing 13 (3.6) 0 (0.0) 13 (4.7)
aAs determined by chi-squared or Fisher’s exact test. bEducation level of survey respondent.
Among the participants, the overall prevalence of doctor-diagnosed asthma was 22.4%; 48.8%
were boys and 51.3% were girls. Statistically significant dierences between asthmatic and
nonasthmatic children were observed for key demographic variables, including language of the
survey, health insurance, and total household income (Table 1). We also observed significant dierences
between asthmatic and nonasthmatic children for respiratory health history variables including
biological mother with asthma (25.1% versus 8.7%, p<0.001), upper respiratory tract infections
before age two (16.3% versus 2.9%, p<0.001), and lower respiratory tract infections before age two
(
32.5% versus 7.9%,
p<0.001) (Table 2). Most doctor diagnoses of asthma had occurred when the child
was between two and four years old (42.5%).
Int. J. Environ. Res. Public Health 2019,16, 3828 5 of 15
Table 2. Respiratory health history of school-age asthmatic and nonasthmatic participants.
Health Characteristics All
N=357 (%)
Asthmatics
N=80 (%)
Nonasthmatics
N=277 (%) p-Value a
Biological mother has asthma
Yes 44 (12.3) 20 (25.1) 24 (8.7) <0.001
No 304 (85.2) 57 (71.3) 247 (89.2)
Missing 9 (2.5) 3 (3.8) 6 (2.2)
Biological mother smoked while
pregnant with child
Yes 16 (4.5) 5 (6.3) 11 (4.0) 0.36
No 333 (93.3) 72 (90.0) 261 (94.2)
Missing 8 (2.2) 3 (3.8) 5 (1.8)
Lower respiratory infection
during infancy
Yes 48 (13.5) 26 (32.5) 22 (7.9) <0.001
No 309 (86.6) 54 (67.5) 255 (92.1)
Upper respiratory infection
during infancy
Yes 21 (5.9) 13 (16.3) 8 (2.9) <0.001
No 336 (94.1) 67 (83.8) 269 (97.1)
Asthma during infancy
Yes 51 (14.3) 47 (58.8) 4 (1.4) <0.001
No 306 (85.7) 33 (41.3) 273 (98.6)
Age of asthma diagnosis b
Under 2 years old 28 (35.0)
2–4 years old 34 (42.5)
5 years old and above 18 (22.5)
aAs determined by chi-squared or Fisher’s exact test. bAmong individuals reporting doctor diagnosis of asthma only.
Respiratory symptoms and allergies were widely reported among this study population (Figure 1;
Supplemental Table S1). The most frequently reported respiratory symptoms and related conditions
in children were wheezing (35.3%), allergies (36.1%), bronchitic symptoms (28.6%), and a dry cough
(33.3%) (Supplemental Table S1). Asthmatics were significantly more likely to report any respiratory
symptoms, but among nonasthmatics we still observed high rates of wheezing (19.9%), allergies (27.4%),
and dry cough (23.1%) (Figure 1). Among those who reported ever having wheezed, 7.9% stated that
wheezing impacted their ability to speak in the past 12 months, 37.3% their ability to exercise in the
past 12 months, and 17.5% their ability to sleep in the past 12 months, as defined as having woken up
due to wheezing more than one night per week (Supplemental Table S2).
Int. J. Environ. Res. Public Health 2019,16, 3828 6 of 15
Int. J. Environ. Res. Public Health 2019, 16, x 6 of 13
Figure 1. Prevalence of reported respiratory symptoms among school-age participants. Bars represent
percentage of asthmatics (n = 80; black bars) and nonasthmatics (n = 277; gray bars) who were reported
to have any of the listed respiratory symptoms in the past 12 months, unless otherwise specified.
We observed statistically significant differences between asthmatics and nonasthmatics in the
use of healthcare resources and respiratory medications, including doctor visits due to wheezing,
emergency room visits due to wheezing, rescue medication use, control medication, and nebulizer
use (Figure 2). Among those who identified as asthmatic, 45.0% and 77.5% reported having gone to
the emergency room or to a doctor, respectively, at least once in their lives for wheezing (Figure 2).
The majority of asthmatics (82.5%) reported that they were currently taking asthma medication, with
80.0% taking rescue medication, 37.5% taking control medication, and 70.0% having used a nebulizer
at least once in the past year. Among the nonasthmatic population, 14.8% of students had been to a
doctor due to wheezing, 7.6% had to go to the emergency room for wheezing, and 9.4% are currently
taking rescue asthma medication raising concerns for potential undiagnosed cases (Figure 2).
Figure 1.
Prevalence of reported respiratory symptoms among school-age participants. Bars represent
percentage of asthmatics (n=80; black bars) and nonasthmatics (n=277; gray bars) who were reported
to have any of the listed respiratory symptoms in the past 12 months, unless otherwise specified.
We observed statistically significant dierences between asthmatics and nonasthmatics in the
use of healthcare resources and respiratory medications, including doctor visits due to wheezing,
emergency room visits due to wheezing, rescue medication use, control medication, and nebulizer
use (Figure 2). Among those who identified as asthmatic, 45.0% and 77.5% reported having gone to
the emergency room or to a doctor, respectively, at least once in their lives for wheezing (Figure 2).
The majority of asthmatics (82.5%) reported that they were currently taking asthma medication,
with 80.0% taking rescue medication, 37.5% taking control medication, and 70.0% having used a
nebulizer at least once in the past year. Among the nonasthmatic population, 14.8% of students had
been to a doctor due to wheezing, 7.6% had to go to the emergency room for wheezing, and 9.4% are
currently taking rescue asthma medication raising concerns for potential undiagnosed cases (Figure 2).
Int. J. Environ. Res. Public Health 2019,16, 3828 7 of 15
Int. J. Environ. Res. Public Health 2019, 16, x 7 of 13
Figure 2. Use of healthcare resources and respiratory medications among school-age asthmatic and
nonasthmatic participants. Bars represent percentage of asthmatics (n = 80; black bars) and
nonasthmatics (n = 277; gray bars) who were reported to have utilized any of the listed healthcare
resources or medications in the past 12 months.
Using logistic regression models, either minimally adjusted (age and sex) or fully adjusted for
covariates (age and sex, plus language of survey, parental education, and school of enrollment), we
examined the association between demographic and household risk factors with physician-
diagnosed asthma (Table 3). Having a biological mother with asthma was associated with a nearly 3-
fold greater odds of asthma (OR: 2.92; 95 CI: 1.445.93) in fully-adjusted models. Exposure to
household environmental tobacco smoke was also associated with 4-fold greater odds of asthma (OR:
4.00; 95% CI: 1.2113.23) in fully adjusted models. Asthma was positively associated with being
enrolled in private insurance (OR: 2.05; 95% CI: 1.153.65) in minimally adjusted models, but this
association was attenuated in the fully adjusted models and no longer statistically significant.
We also investigated the influence of various housing characteristics on the asthma prevalence
in our population (Table 3). Although most housing characteristics did not significantly differ
between asthmatics and nonasthmatics (Supplemental Table S3), we did observe differences in
asthma prevalence across minimally and fully adjusted models associated with length of cooking gas
use in the home and the presence of pets. Asthma prevalence was marginally associated with using
a gas stove for more than 1 h per day (OR: 2.58; 95% CI: 0.97–6.82) (Table 3) in fully adjusted models.
About one-third of participants reported having a furry pet at home (29.4%) (Supplemental Table S3),
which was observed to be negatively associated with odds of asthma (OR: 0.42; 95% CI: 0.210.82) in
fully adjusted models (Table 3).
Table 3. Associations between individual demographic and household risk factors and the prevalence
of asthma.
Figure 2.
Use of healthcare resources and respiratory medications among school-age asthmatic
and nonasthmatic participants. Bars represent percentage of asthmatics (n=80; black bars) and
nonasthmatics (n=277; gray bars) who were reported to have utilized any of the listed healthcare
resources or medications in the past 12 months.
Using logistic regression models, either minimally adjusted (age and sex) or fully adjusted
for covariates (age and sex, plus language of survey, parental education, and school of
enrollment), we examined the association between demographic and household risk factors with
physician-diagnosed asthma (Table 3). Having a biological mother with asthma was associated with a
nearly 3-fold greater odds of asthma (OR: 2.92; 95 CI: 1.44–5.93) in fully-adjusted models. Exposure
to household environmental tobacco smoke was also associated with 4-fold greater odds of asthma
(OR: 4.00; 95% CI: 1.21–13.23) in fully adjusted models. Asthma was positively associated with being
enrolled in private insurance (OR: 2.05; 95% CI: 1.15–3.65) in minimally adjusted models, but this
association was attenuated in the fully adjusted models and no longer statistically significant.
We also investigated the influence of various housing characteristics on the asthma prevalence in
our population (Table 3). Although most housing characteristics did not significantly dier between
asthmatics and nonasthmatics (Supplemental Table S3), we did observe dierences in asthma prevalence
across minimally and fully adjusted models associated with length of cooking gas use in the home and
the presence of pets. Asthma prevalence was marginally associated with using a gas stove for more
than 1 h per day (OR: 2.58; 95% CI: 0.97–6.82) (Table 3) in fully adjusted models. About one-third of
participants reported having a furry pet at home (29.4%) (Supplemental Table S3), which was observed
to be negatively associated with odds of asthma (OR: 0.42; 95% CI: 0.21–0.82) in fully adjusted models
(Table 3).
Int. J. Environ. Res. Public Health 2019,16, 3828 8 of 15
Table 3. Associations between individual demographic and household risk factors and the prevalence of asthma.
Characteristics Minimally Adjusted a
OR (95% CI) p-Value Fully Adjusted b
OR (95% CI) p-Value
Participant demographics
Household Income c1.05 (0.89–1.24) 0.53 1.05 (0.88–1.25) 0.62
Health insurance
Public Ref. – Ref. –
Private 2.05 (1.15–3.65) 0.02 1.68 (0.89–3.15) 0.11
None 0.53 (0.18–1.59) 0.26 0.49 (0.16–1.55) 0.23
Household environmental smoke
No Ref. – Ref. –
Yes 4.24 (1.37–13.07) 0.01 4.00 (1.21–13.23) 0.02
Biological mother smoked while pregnant
No Ref. – Ref. –
Yes 1.66 (0.55–4.94) 0.37 2.23 (0.59–8.30) 0.23
Biological mother has asthma
No Ref. – Ref. –
Yes 3.79 (1.94–7.39) <0.001 2.92 (1.44–5.93) 0.003
Play sports at least twice a week
No Ref. – Ref. –
Yes 1.43 (0.85–2.42) 0.17 1.62 (0.93–2.83) 0.09
Housing characteristics
Housing type
Home Ref. – Ref. –
Apartment 0.97 (0.56–1.68) 0.97 1.00 (0.55–1.80) 0.99
Mobile home or trailer 0.86 (0.35–2.10) 0.74 1.73 (0.62–4.82) 0.29
Gas cooking stove
No Ref. – Ref. –
Yes 0.59 (0.31–1.12) 0.11 0.65 (0.32–1.34) 0.25
Length of daily gas stove use
Less than 30 min Ref. – Ref. –
Less than 1 h 1.45 (0.77–2.70) 0.25 1.42 (0.74–2.75) 0.29
More than 1 h 3.17 (1.31–7.65) 0.01 2.58 (0.97–6.82) 0.06
Int. J. Environ. Res. Public Health 2019,16, 3828 9 of 15
Table 3. Cont.
Characteristics Minimally Adjusted a
OR (95% CI) p-Value Fully Adjusted b
OR (95% CI) p-Value
Home heater
No Ref. – Ref. –
Yes 2.46 (1.06–5.68) 0.04 2.08 (0.87–4.94) 0.10
Water damage in home
No Ref. – Ref. –
Yes 2.23 (1.00–4.98) 0.05 1.73 (0.74–4.02) 0.21
Mold in home
No Ref. – Ref. –
Yes 1.37 (0.69–2.73) 0.37 1.21 (0.59–2.48) 0.60
Musty odor in home
No Ref. – Ref. –
Yes 2.56 (0.85–7.74) 0.10 2.14 (0.67–6.88) 0.20
Carpet in home
No Ref. – Ref. –
Yes 1.32 (0.78–2.25) 0.30 1.53 (0.86–2.72) 0.15
Child has lived in same house for whole life
No Ref. – Ref. –
Yes 1.32 (0.77–2.30) 0.31 1.29 (0.71–2.35) 0.41
Pet ownership
None Ref. – Ref. –
Furry pet 0.48 (0.26–0.91) 0.02 0.42 (0.21–0.82) 0.01
Other pets 1.17 (0.48–2.83) 0.74 0.87 (0.34–2.24) 0.77
Regular contact with farm animals
No Ref. – Ref. –
Yes 1.21 (0.57–2.57) 0.62 1.52 (0.67–3.45) 0.32
Problem with rodents in the home
No Ref. – Ref. –
Yes 0.90 (0.36–2.20) 0.81 0.84 (0.33–2.13) 0.72
Problem with insects in the home
No Ref. – Ref. –
Yes 1.19 (0.66–2.16) 0.57 0.97 (0.51–1.82) 0.92
a
Minimally adjusted model includes age and sex as covariates.
b
Fully adjusted model includes age, sex, language, parental education, and school as covariates.
c
Modeled as a
continuous variable.
Int. J. Environ. Res. Public Health 2019,16, 3828 10 of 15
4. Discussion
Our study sought to characterize the prevalence rates of asthma and other respiratory conditions
among rural, predominantly Mexican-American elementary school children living near the Salton
Sea in the Imperial Valley, CA prior to the implementation of the water transfer agreement poised to
dramatically accelerate the shrinking of this saline lake. Using parent-reported survey information,
we observed an overall asthma prevalence of 22.4%, which is significantly higher than the national
average for children ages 5–11 years (8.8%), the national average for Mexican-American children ages
0 to 17 (6.2%), and the California state rates for children ages 0 to 17 (14.5%) [
1
,
22
,
23
]. In addition
to asthma, we observed high rates of various respiratory symptoms, including wheezing (35%),
allergies (36%), bronchitic symptoms (28%), and persistent dry cough (33%), which were widely
reported among both asthmatic and nonasthmatic children. We also identified sociodemographic
and household factors that may be related to asthma. The findings of this study provide evidence
to support community concerns about children’s respiratory health, suggesting that household and
demographic characteristics have limited explanatory power for assessing asthma in this population.
Our study provides critical baseline data with which to evaluate the eect of local environmental
exposures on asthma and respiratory symptoms.
A small number of similar studies have investigated asthma prevalence and respiratory health
in the USA–Mexico border areas. Together, these studies collectively suggest higher rates of asthma
and respiratory illness along the U.S. side [
6
,
24
26
]. Our findings were similar to those of several
other studies among children living in largely urban border areas, including a study conducted
on the Arizona–Sonora border, which estimated a 25.8% rate of asthma among adolescents aged
13–14 [
6
]. A study looking at the prevalence of children’s respiratory health conditions in El Paso,
TX reported a similar asthma rate of 17% among fourth and fifth graders [
24
]. Our estimates are,
however, much higher than those observed in other studies from Texas [
25
], and among similarly
aged fifth-grade students in the Nogales, Mexico/Arizona border region [
26
], which found asthma
prevalence rates ranging from 5.8% to 9.4%. To our knowledge, the Border Asthma and Allergies
(BASTA) study is the only other study of respiratory health outcomes to have been conducted in
the Imperial Valley; it found an asthma prevalence of 20% among students aged 13–14, which is
comparable to our observed rate of 22.4%. However, compared to our study, the BASTA study found
higher reported rates of allergies among participants (57% versus 36%) [
8
]. Among children living
in the Coachella Valley, a rural community north of the Salton Sea, 17.5% of sampled children were
asthmatic or had a persistent cough [
27
]. Although similarities exist across these various studies,
caution must be exercised as other studies may have used dierent assessment instruments or criteria
to determine asthma prevalence.
Our results also suggest the possibility of underdiagnosis of asthma and respiratory impairment
in our school-age population. A number of studies have suggested that there may be a substantial
number of children who report asthma-like symptoms but remain undiagnosed [
28
32
]. Prior work
in USA–Mexico border communities found that, among those who reported wheezing, there was
a high risk of possible undiagnosed asthma [
22
,
31
]. In our sample of school children, nearly one
in five nonasthmatics reported having at least one episode of wheezing in their lifetime, nearly one
in seven reported having ever visited the doctor due to wheezing, and about one in 13 reported
ever having gone to the ER due to wheezing. Substantial proportions of nonasthmatic children
reported a persistent dry cough at night, bronchitic symptoms, or the recent use of an asthma rescue
medication. Among nonasthmatics who reported having at least one episode of wheezing in their
lifetime, half experienced wheezing in the past 12 months, and a quarter experienced wheezing after
exercise. Given the large number of children in our population who reported respiratory symptoms
without an asthma diagnosis, this suggests more widespread respiratory impairment in this population.
Prior research found that children not diagnosed with asthma, but reporting wheezing-like
symptoms, experienced missed school days, limitation of physical activities, and sleep disturbances [
29
].
Similar to our findings, 7% of children with current asthma-like symptoms but no diagnosis in a
Int. J. Environ. Res. Public Health 2019,16, 3828 11 of 15
North Carolina-based school study reported an emergency department visit due to an episode of
wheezing [
29
]. In a similar study conducted by van Gent et al., children with undiagnosed asthma had
lower quality-of-life scores than healthy control individuals, and also experienced, on average, a more
than one week longer absence from school over 12 months because of respiratory symptoms compared
to healthy individuals [
28
]. Children may have increased vulnerability to environmental insults,
particularly in this region, and future work will further investigate the impact of breathing diculties
on quality of life across both asthmatic and nonasthmatic children in our study population [33].
Our health survey collected information from parents on a number of sociodemographic, lifestyle,
and household characteristics that may be related to children’s respiratory health. When we examined
maternal health factors, we found that having a biological mother with asthma was strongly related
to child asthma and was consistent across all models tested. This is expected as family history and
genetic predisposition are important components of asthma risk [
34
,
35
]. Additionally, as reported by
numerous studies, we observed that maternal smoking during pregnancy increased the odds of child
asthma; however, this was based on a relatively small number of mothers who reported smoking,
and this association did not reach statistical significance [3638].
Conditions in the indoor home environment have frequently been associated with children’s asthma
risk and respiratory symptoms. In line with previous studies, we observed a strong positive association
between exposure to household environmental tobacco smoke and asthma diagnosis [
34
,
39
,
40
]. We also
observed a positive association between the use of a gas stove for more than 1 h per day and asthma
diagnosis. Previous studies have found that gas stoves release respiratory irritants and may increase
the risk of respiratory symptoms and asthma exacerbations in children [
41
]. Although other studies
have reported other significant risk factors in the home such as water damage or carpeting, we did
not observe significant associations between these variables and asthma in our analyses [19,27,34,35].
Having a furry pet at home was negatively associated with asthma in our study population. This is
contrary to some other findings, although pet ownership has been inconsistently associated with
asthma and allergic symptoms in various studies [
42
44
]. Despite this being a heavily agricultural
community, no significant associations were found between reporting an asthma diagnosis and having
regular contact with a farm animal. Further investigation of the role of exposure to pets and other
animals in asthma is warranted, given the conflicting findings across studies.
Our study of rural, primarily Mexican-American elementary school children provides novel
insights into the factors impacting respiratory health in the Imperial Valley. Our assessment benefited
from the collection of numerous demographic, lifestyle, and home characteristics and the use of
validated questionnaires to assess a variety of respiratory health symptoms. However, our study was
also limited by several factors. In this study, we relied on the respondents’ questionnaire answers to
assess asthma diagnosis, rather than medical records or physical examination. It is possible that defining
asthma according to self-reported doctor diagnosis may have resulted in some outcome misclassification
among our participants. Furthermore, it is possible that parents/guardians of asthmatics or those
who were concerned about their child’s respiratory health were more likely to complete the survey
than parents of nonasthmatic children, which could have led to over- or under-representation of
symptoms and exposures. Lastly, although we examined numerous potential factors, we cannot rule
out the possibility of residual confounding in our models. The limited ability of demographic, lifestyle,
and other known risk factors, such as housing characteristics, to explain the high observed rates of
asthma (22.4%) and respiratory symptoms in this young population suggests that environmental
factors are likely contributors.
Rural communities in the southwestern USA and along the USA–Mexico border face changing
weather patterns, droughts, and competing water demands that are dramatically altering the landscape
and creating conditions conducive to the production of wind-blown dust. As the Salton Sea recedes,
primarily due to local changes in water supplies and reductions in agricultural runo, it is anticipated
that 40–80 more tons of dust per day will be released into the local environment [
45
], exposing large
swaths of playa and generating wind-blown dust [
13
]. Because the particulates from dried lakebeds
Int. J. Environ. Res. Public Health 2019,16, 3828 12 of 15
have been shown to be smaller in size, they are more easily respirable by humans [
46
], and such
substantial increases in dust have the potential to significantly impact the respiratory health and quality
of life for nearby residents [
9
12
]. This impact is expected to be seen first along the southern edge of the
Sea, where our findings show that, overall, children are already disproportionally aected by asthma.
Follow-up studies of these children are underway to explore the eects of a changing environment on
respiratory health.
Our findings may help provide a better understanding of the health needs of the community,
as well as strategies to inform community-specific preventive programs to address the symptoms of
asthma and respiratory impairment. The disappearance of the Salton Sea will likely have unforeseen
public health implications, while children and people with preexisting health conditions, such as asthma,
may be more vulnerable to the impacts of such environmental changes [
13
,
47
,
48
]. Future research
will longitudinally examine children’s respiratory health, incorporating both ambient exposure
measurements and physiological assessments over time. While this work began as a way to provide a
baseline assessment of children’s health in relation to the shrinking of Salton Sea, the broad implications
of the present research reveal a public health and environmental justice crisis that requires action,
attention, and further research to protect the health and wellbeing of local communities.
Supplementary Materials:
The following are available online at http://www.mdpi.com/1660-4601/16/20/3828/s1,
Table S1: Prevalence of respiratory symptoms, health care utilization and medication use among school-age
participants (n=357), Table S2: Impact of wheezing among asthmatic and non-asthmatic participants reporting
any lifetime wheeze (N =126); Table S3: Housing characteristics among study participants (N =357).
Author Contributions:
Conceptualization and Methodology, S.F.F. and J.E.J.; Formal Analysis, M.R., S.P.E.,
S.F.F., and J.E.J.; Investigation, S.F.F., J.E.J.; Resources, S.F.F., J.E.J.; Data Curation, M.R.; Writing—Original Draft
Preparation, M.R., S.F.F., and J.E.J.; Writing—Review & Editing, M.R., S.P.E., L.O., E.B., S.F.F., and J.E.J.; Supervision,
L.O., E.B., S.F.F., and J.E.J.; Project Administration, L.O., E.B., S.F.F., and J.E.J.; Funding Acquisition, L.O., S.F.F.,
and J.E.J.
Acknowledgments:
We thank the participating elementary schools, parents, and students for their collaboration
and dedication to support health in their community. In particular, we are grateful for the eorts of Comite
Civico del Valle and the Children’s AIRE Study sta. Funding for this study was provided by NIEHS R01
(1R01ES029598-01), the NIEHS Southern California Environmental Health Sciences Center (5P30ES007048-20),
and a pilot grant from the Keck School of Medicine of USC Dean’s Pilot Program.
Conflicts of Interest:
The authors declare no conflict of interest. The sponsors that supported this work had no
role in the design, execution, interpretation, or writing of the study.
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©
2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access
article distributed under the terms and conditions of the Creative Commons Attribution
(CC BY) license (http://creativecommons.org/licenses/by/4.0/).
... The Salton Sea's main water source today has been reduced to primarily agricultural runoff [28]; between drought and water politics, the Salton Sea's water levels are dropping, its borders receding, and its salinity increasing-exposing emissive surfaces increasing wind-blown dust and contributing toxic air contaminants, including ammonia and sulfur dioxide gases [29][30][31]. Dust storms transport exposed playa containing toxic metals, pesticides, and other toxins into the communities and homes of those living along its borders, which may contribute to severe health conditions such as asthma and other respiratory distress [32,33]. ...
... There is a disproportionate prevalence of respiratory illness in the ECV. Approximately 20-22.4% of children living along the Salton Sea meet the diagnostic criteria for asthma or other respiratory illness [33], compared to 10% for children in California and 11.3% in the U.S. as a whole [43]. Participants at all in-home meetings raised concerns about the prevalence of respiratory illness in the ECV, linking the local decline of respiratory health to environmental exposure via the interrelation of the Salton Sea and their agricultural labor. ...
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Full-text available
Workplace and environmental exposures pose health risks for racial/ethnic minorities in rural agricultural communities, placing them at a disadvantage in accessing needed health care. Over three fourths (76%) of the 2.4 million farmworkers in the United States are immigrants, mostly from Mexico. However, little is known of the community health concerns and barriers to care of Latinx farmworkers in inland southern California. This qualitative study used a community-based participatory research approach, conducting nine in-home meetings to obtain meaningful community input on health concerns and barriers to access healthcare services among rural residents of the Eastern Coachella Valley, who are also located near the desert-bound Salton Sea of inland southern California. All interviews were audio-recorded and analyzed via listening to the audio recordings and summarizing data in templates and matrices. Participants discussed health concerns related to agricultural labor, including heat-related illness, musculoskeletal ailments and injuries, skin disorders, respiratory illness, and trauma. Participants raised concerns about environmental exposures related to agriculture and the nearby Salton Sea, a highly saline lakebed, and proposed solutions to improve the health of their communities. The findings from this study suggest farmworkers are aware of the health risks posed by living and working in rural farmlands but lack resources and information to act upon and advocate for improved public health.
... Along with high levels of dust, the communities surrounding the Salton Sea have high levels of childhood asthma. Currently, the asthma rate among children is estimated at 20 %-22.4 %, which is among the highest in the state of California, and noticeably higher than the state average of 14.5 % (Farzan et al., 2019). Additionally, the communities surrounding the Salton Sea are among the top percentile for emergency room visits due to asthma (California Environmental Protection Agency and Office of Environmental Health Hazard Assessment, 2021), though whether this is due to more severe asthma, lack of access to healthcare, high asthma rates, or a combination thereof is currently unknown. ...
Article
Background A high incidence of asthma is prevalent among residents near the Salton Sea, a large inland terminal lake in southern California. This arid region has high levels of ambient particulate matter (PM); yet while high PM levels are often associated with asthma in many environments, it is possible that the rapidly retreating lake, and exposed playa or lakebed, may contribute components with a specific role in promoting asthma symptoms. Objectives Our hypothesis is that asthma may be higher in residents closest to the Salton Sea due to chronic exposures to playa dust. Playa emissions may be concentrating dissolved material from the lake, with microbial components capable of inducing pulmonary innate immune responses. To test this hypothesis, we used a mouse model of aerosol exposures to assess the effects of playa dust. Methods From dust collected around the Salton Sea region, aqueous extracts were used to generate aerosols, which were injected into an environmental chamber for mouse exposure studies. We compared the effects of exposure to Salton Sea aerosols, as well as to known immunostimulatory reference materials. Acute 48-h and chronic 7-day exposures were compared, with lungs analyzed for inflammatory cell recruitment and gene expression. Results Dust from sites nearest to the Salton Sea triggered lung neutrophil inflammation that was stronger at 48-h but reduced at 7-days. This acute inflammatory profile and kinetics resembled the response to innate immune ligands LTA and LPS while distinct from the classic allergic response to Alternaria. Conclusion Lung inflammatory responses to Salton Sea dusts are similar to acute innate immune responses, raising the possibility that microbial components are entrained in the dust, promoting inflammation. This effect highlights the health risks at drying terminal lakes from inflammatory components in dust emissions from exposed lakebed.
... Through these kinds of techniques, responses from under-represented demographics can be weighted more heavily to better match target demographic ratios. Furthermore, seeking out communication, collaboration, and data collection opportunities within the communities least likely to either self-report or make use of emergency services will help policymakers and researchers better understand the specific health needs and opportunities to assist those who are most impacted by current and projected pollution in the Coachella Valley (Cheney et al., 2018;Farzan et al., 2019;Kim et al., 2020;Rodriguez et al., 2020). Many other factors may also contribute to errors and biases within collected data. ...
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The ongoing desiccation of California's Salton Sea has led to increasing concerns about air quality and health for its surrounding communities, including the nearby Coachella Valley – a region already experiencing severe air quality and health disparities. Here we explore spatial air pollution and human health disparities in the Coachella Valley with particular attention to disparities arising across population characteristics including both socioeconomic and demographic vulnerabilities. We use two different measures of respiratory and cardiovascular health outcomes at the individual and census tract levels – one measure based on a randomly sampled telephone survey and the other measure based on emergency room visitation data – to investigate the degree to which these health outcomes are connected to air pollution and socioeconomic metrics. We further investigate biases and differences between the health outcome metrics themselves and suggest opportunities to address them in future analyses and survey efforts. We find that more vulnerable communities are associated with higher levels of fine particulates, but lower levels of ozone. While emergency visit rates show a significant positive correlation with both pollutants, no such association is found when using surveyed health outcome data. The ratio of emergency visits versus survey rates shows a positive relationship with socioeconomic and demographic vulnerability, indicating that vulnerable communities are less likely to self-report diagnoses despite higher rates of respiratory or cardiovascular hospitalization. Additionally, survey respondents tend to show less vulnerability relative to their surrounding census-based demographics. These findings suggest the need for greater attention to health issues specifically within disadvantaged communities in the Coachella Valley, building upon and working within existing community networks and local resources, to better address current and projected health needs. Our findings also highlight disparities in air pollution exposure, health outcomes, and population characteristics in the Coachella Valley, providing context for crucial pollution reduction efforts in the face of increasing environmental threats.
... High levels of particulate matter in the air, as well as air pollution from agricultural burning, automobile exhaust and factory emissions from surrounding regions, have contributed to high asthma rates in Imperial County [5]. Approximately 15.1% of Imperial County's population is affected by asthma [6], with pediatric asthma-related emergency room visits and hospitalizations that double the California state average [7]. ...
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The area surrounding California's Salton Sea, which lies within Riverside and Imperial counties, has particularly negative health outcomes. Imperial County, a primarily rural region that encompasses the lake, has pediatric asthma-related emergency healthcare visits that double the state average. This paper seeks to assess the level of emergency healthcare access in the Salton Sea region of Imperial County, drawing from spatial science methods. For this study, the "Salton Sea region" is defined as all Imperial County census tracts that include the Salton Sea within its boundaries. To measure "access," this study calculated driving travel times from census tracts to hospitals within Imperial County rather than Euclidean distance to account for geography and urban infrastructures such as road networks and traffic conditions. This study also used the Rational Agent Access Model, or RAAM, to assess access. RAAM scores account for the supply and demand for hospitals in addition to travel times. Results showed that the average travel time for Salton Sea region residents to drive to Imperial County emergency healthcare facilities ranged from 50-61 minutes, compared to 14-20 minutes for other Imperial County tracts. RAAM scores, compared to other Imperial County tracts, were about 30% higher in the Salton Sea region, meaning that healthcare supply is limited in the region. State and county policy should account for spatial inaccessibility to healthcare institutions in order to address emergency healthcare access.
... The county is mainly desert and agricultural land, with a range of air pollution sources-such as field burning, the U.S.-Mexico border crossing, unpaved roads, and various industrial facilities-that contribute to exceedances of the California standard for particulate matter of 10µm or less (PM 10 ) for time periods lasting over six months [23,24]. Historically, Imperial County far surpasses all other California counties as having the highest rate of both emergency visits and hospitalizations for asthma among school-age children [25], and a recent study suggests that respiratory impairment may be underdiagnosed in this population [26]. PM10 is related to increased respiratory disease, decreased lung function, and asthma attacks in susceptible individuals [27]. ...
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Initiated in response to community concerns about high levels of air pollution and asthma, the Imperial County Community Air Monitoring Project was conducted as a collaboration between a community-based organization, a non-governmental environmental health program, and academic researchers. This community-engaged research project aimed to produce real-time, community-level air quality information through the establishment of a community air monitoring network (CAMN) of 40 low-cost particulate matter (PM) monitors in Imperial County, California. Methods used to involve the community partner organization and residents in the development, operation, and use of the CAMN included the following: (1) establishing equitable partnerships among the project collaborators; (2) forming a community steering committee to guide project activities; (3) engaging residents in data collection to determine monitor sites; (4) providing hands-on training to assemble and operate the air monitors; (5) conducting focus groups to guide display and dissemination of monitoring data; and (6) conducting trainings on community action planning. This robust community engagement in the project resulted in increased awareness, knowledge, capacity, infrastructure, and influence for the community partner organization and among community participants. Even after the conclusion of the original research grant funding for this project, the CAMN continues to be operated and sustained by the community partner, serving as a community resource used by residents, schools, researchers, and others to better understand and address air pollution and its impacts on community health, while strengthening the ability of the community to prepare for, respond to, and recover from harmful air pollution.
... The human population surrounding the Salton Sea includes a high proportion of migrant workers, with high rates of poverty and poor access to health care. Area residents suffer from one of the highest rates of childhood asthma in California at 20%-22.4%, compared to an average of 14.5% for the rest of the State (Farzan et al., 2019). Predictably, the surrounding area also has one of the highest rates of hospitalization for asthma (California Environmental Protection Agency, 2018), making it a serious health crisis in an already underserved community. ...
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In communities surrounding the Salton Sea, high rates of asthma are associated with high aerosol dust levels. However, the Salton Sea itself may play an additional role in pulmonary health. Therefore, to investigate a potential role of the Salton Sea on pulmonary health, we exposed mice to aerosolized Salton Sea water for 7 days and assessed tissue responses, including cellular infiltration and gene expression changes. For reference, mice were also exposed to aerosolized fungal allergen (Alternaria sp.) and Pacific Ocean aerosols. Exposure to aerosolized Alternaria sp. induced dramatic allergic inflammation, including neutrophil and eosinophil recruitment to the bronchoalveolar lavage fluid (BALF) and lung tissue. By contrast, Salton Sea “spray” induced only B cell recruitment to the lung tissue without increased inflammatory cell numbers in BALF. However, there were consistent gene expression changes suggestive of an inflammatory response. The response to the Salton Sea spray was notably distinct from the response to Pacific Ocean water, which induced some B cell recruitment but without an inflammatory gene expression profile. Our studies suggest that soluble components in Salton Sea water promote induction of a unique inflammation-associated response, though any relationship to asthma remains to be explored.
Research
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In part two of this multi-part ArcGIS StoryMap series, we discuss what the University of California, Riverside is doing to redefine environmental and public health issues with communities around the Salton Sea. More specifically, we focus on the researchers who are affiliated with the University of California, Riverside's Center for Health Disparities Research (HDR@UCR). The interactive ArcGIS StoryMap may be accessed via https://storymaps.arcgis.com/stories/d93d73ca89a84023aa09d0a38202daaf.
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Conventional regulatory air quality monitoring sites tend to be sparsely located. The availability of lower-cost air pollution sensors, however, allows for their use in spatially dense community monitoring networks, which can be operated by various stakeholders, including concerned residents, organizations, academics, or government agencies. Networks of many community monitors have the potential to fill the spatial gaps between existing government-operated monitoring sites. One potential benefit of finer scale monitoring might be the ability to discern elevated air pollution episodes in locations that have not been identified by government-operated monitoring sites, which might improve public health warnings for populations sensitive to high levels of air pollution. In the Imperial Air study, a large network of low-cost particle monitors was deployed in the Imperial Valley in Southeastern California. Data from the new monitors is validated against regulatory air monitoring. Neighborhood-level air pollution episodes, which are defined as periods in which the PM2.5 (airborne particles with sizes less than 2.5 μm in diameter) hourly average concentration is equal to or greater than 35 μg m−3, are identified and corroborate with other sites in the network and against the small number of government monitors in the region. During the period from October 2016 to February 2017, a total of 116 episodes were identified among six government monitors in the study region; however, more than 10 times as many episodes are identified among the 38 community air monitors. Of the 1426 episodes identified by the community sensors, 723 (51%) were not observed by the government monitors. These findings suggest that the dense network of community air monitors could be useful for addressing current limitations in the spatial coverage of government air monitoring to provide real-time warnings of high pollution episodes to vulnerable populations.
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This study aimed to estimate the number of incident cases and hospital admissions attributable to secondhand smoke (SHS) exposure at home for asthma, otitis media (OM), and lower respiratory infections (LRI) in children in Spain. The burden of respiratory disease caused by SHS exposure was estimated in terms of incident cases and hospitalized cases for asthma, OM, and LRI. Estimates were calculated using the population attributable fraction. The age-specific (0-1 year, 0-4 years, 5-11 years, and 0-11 years) prevalence of SHS exposure in children was estimated through a telephone survey performed in a representative sample of Spanish households with children in 2016. The risk estimates for all diseases were selected from international meta-analyses. The number of hospitalized cases was obtained for each disease from the Hospital Minimum Data Set provided by the Ministry of Health of Spain. Incident cases were obtained from the Global Health Data Exchange. In 2015, SHS exposure caused an estimated total of 136,403 incident cases of the following respiratory diseases: 9058 (8.5%) cases of asthma, 120,248 (8.5%) of OM, and 7097 (13.5%) of LRI in children aged 0-14 years old in Spain. Likewise, SHS exposure caused a total of 3028 hospitalized cases, with 379 (8.5%) for asthma and 167 (8.5%) for OM in children 0-11 years old, and 2482 (11.6%) for LRI in children <2 years old. The high burden of respiratory disease attributed to SHS exposure supports the need to improve protection of children against SHS exposure by extending smoke-free regulations to homes and cars.
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Changing weather patterns, droughts and competing water demands are dramatically altering the landscape and creating conditions conducive to the production of wind-blown dust and dust storms. In California, such factors are leading to the rapid shrinking of the Salton Sea, a 345 mile2 land-locked "sea" situated near the southeastern rural border region known as the Imperial Valley. The region is anticipated to experience a dramatic increase in wind-blown dust and existing studies suggest a significant impact on the health and quality of life for nearby residents of this predominantly low-income, Mexican-American community. The discussion calls attention to the public health dimensions of the Salton Sea crisis. We know little about the possible long-term health effects of exposure to mobilized lakebed sediments or the numerous toxic contaminants that may become respirable on entrained particles. We draw on existing epidemiological literature of other known sources of wind-blown dust, such as desert dust storms, and related health effects to begin to understand the potential public health impact of wind-blown dust exposure. The increased production of wind-blown dust and environmental exposures to such non-combustion related sources of particulate matter are a growing health threat, due in part to drought coupled with increasing pressures on limited water resources. Recent population-based studies have linked dust storms with cardiovascular mortality, asthma hospitalization and decrease in pulmonary function in both adults and children. A growing number of studies provide evidence of the acute health effects of wind-blown dust exposures among children, which with repeated insults have the potential to influence respiratory health over time. The shrinking of the Salton Sea illustrates a public health and environmental justice crisis that requires action and attention to protect the health and well-being of local communities.
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Indoor mold contamination has been associated in many studies with an increased risk of asthma and respiratory illness. This study investigated indoor mold contamination and the prevalence of asthma/respiratory illness in two low-income, Hispanic communities, Mecca and Coachella City, in the Eastern Coachella Valley (ECV) of California. The study consisted of a questionnaire to assess asthma/respiratory illness and the quantification of mold contamination in house dust samples using the Environmental Relative Moldiness Index (ERMI) scale. About 11% of the adults and 17% of the children in both Mecca and Coachella City met our definitions of asthma/respiratory illness. The average ERMI values in Mecca and Coachella City housing (10.3 and 6.0, respectively) are in the top 25% of ERMI values for the United States (US) homes. Overall, the homes surveyed in these ECV communities had an average prevalence of occupant asthma of 12.8% and an average ERMI value of 9.0. The prevalence of asthma/respiratory illness in the Hispanic communities of Mecca and Coachella City and the mold contamination in their homes appear to be greater than the averages for the rest of the US. The higher levels of mold contamination in their homes appear to be associated with a greater risk of asthma/respiratory illness for these low-income, Hispanic communities.
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Air pollution continues to be a global public health threat, and the expanding availability of small, low-cost air sensors has led to increased interest in both personal and crowd-sourced air monitoring. However, to date, few low-cost air monitoring networks have been developed with the scientific rigor or continuity needed to conduct public health surveillance and inform policy. In Imperial County, California, near the U.S./Mexico border, we used a collaborative, community-engaged process to develop a community air monitoring network that attains the scientific rigor required for research, while also achieving community priorities. By engaging community residents in the project design, monitor siting processes, data dissemination, and other key activities, the resulting air monitoring network data are relevant, trusted, understandable, and used by community residents. Integration of spatial analysis and air monitoring best practices into the network development process ensures that the data are reliable and appropriate for use in research activities. This combined approach results in a community air monitoring network that is better able to inform community residents, support research activities, guide public policy, and improve public health. Here we detail the monitor siting process and outline the advantages and challenges of this approach.
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Maternal smoking in pregnancy (MSP) is a large modifiable risk factor for pregnancy related mortality and morbidity and also the most important known modifiable risk factor for asthma. This review summarises the effects of MSP throughout infancy, childhood and adolescence with regards to asthma (development and severity). Firstly, the direct damage caused by nicotine on fetal lung development, fetal growth and neuronal differentiation is discussed, as well as the indirect effects of nicotine on placental functioning. Secondly, the effects of MSP on later immune functioning resulting in increased infection rate are summarised and details are given on the effects of MSP modulating airway hyperreactivity, reducing lung function and therefore increasing asthma morbidity. Furthermore, epigenetic effects are increasingly being recognised. These can also result in transgenerational detrimental effects induced by cigarette smoke. In summary, the causal relationship between MSP and asthma development is well documented and presents a major health problem for generations to come. The high prevalence of MSP is alarming and epigenetic effects of nicotine on immune functioning potentiate this danger. A considerable part of the increase in asthma prevalence worldwide is due to MSP.
Article
Objective Among high-risk, underserved populations, such as children living along the US-México border, suffering from asthma-like symptoms without an asthma diagnosis can result in a high burden of illness. We estimated the prevalence of physician-diagnosed and possible undiagnosed asthma among students with histories of wheezing in the US-México border community of El Paso, Texas, and evaluated their burden of illness, primary care use, and medication utilization. Methods We analyzed cross-sectional survey data collected in May 2012. The survey included validated International Study of Asthma and Allergies in Childhood (ISAAC) items. We performed bivariate and logistic regression analyses on data from 307 students who wheezed. Results Forty-two percent of students had possible undiagnosed asthma and 58% had physician-diagnosed asthma based on primary caretaker reports. Children of Mexican origin were more likely to report undiagnosed vs. diagnosed asthma (p < 0.05). Children with an asthma diagnosis were more likely to report any medication use for wheezing/asthma and to experience a higher burden of illness in the last year compared to students with possible undiagnosed asthma (p < 0.05). Conclusions The burden of illness among these children was high; however, children with asthma-like symptoms were not faring worse than children with asthma symptoms and a diagnosis. Undiagnosed children were being evaluated and receiving treatment for their symptoms; however, by not receiving a diagnosis, they were eliciting an ameliorative rather than preventive treatment strategy.
Article
Background: Secondhand smoke (SHS) exposures have been linked to asthma-related outcomes but quantitative dose-responses using biomarkers of exposure have not been widely reported. Objectives: Assess dose-response relationships between plasma cotinine-determined SHS exposure and asthma outcomes in minority children, a vulnerable population exposed to higher levels of SHS and under-represented in the literature. Methods: We performed analyses in 1172 Latino and African-American children with asthma from the mainland USA and Puerto Rico. We used logistic regression to assess relationships of cotinine levels ≥0.05 ng/mL with asthma exacerbations (defined as asthma-related hospitalisations, emergency room visits or oral steroid prescription) in the previous year and asthma control. The shape of dose-response relationships was assessed using a continuous exposure variable in generalised additive logistic models with penalised splines. Results: The OR for experiencing asthma exacerbations in the previous year for cotinine levels ≥0.05 ng/mL, compared with <0.05 ng/mL, was 1.40 (95% CI 1.03 to 1.89), while the OR for poor asthma control was 1.53 (95% CI 1.12 to 2.13). Analyses for dose-response relationships indicated increasing odds of asthma outcomes related with increasing exposure, even at cotinine levels associated with light SHS exposures. Conclusions: Exposure to SHS was associated with higher odds of asthma exacerbations and having poorly controlled asthma with an increasing dose-response even at low levels of exposure. Our results support the conclusion that there are no safe levels of SHS exposures.
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Asthma is diagnosed based on patients' respiratory symptoms of wheeze, cough, chest tightness and/or dyspnea together with physiologic evidence of variable and reversible expiratory airflow limitation. In the United States 7.6% of adults and 8.4% of children self-report a physician diagnosis of current asthma. Population-based studies in children, adults and the elderly suggest that from 20% to 70% of asthmatics in the community remain undiagnosed and hence untreated. Under-diagnosis of asthma has been found to be associated with under-reporting of respiratory symptoms by patients to their physicians as well as poor socio-economic status. On the opposite side of the spectrum, studies of patients with physician-diagnosed asthma suggest that 30%-35% of adults and children diagnosed with asthma do not have current asthma, suggesting that asthma is also over-diagnosed in the community. Over-diagnosis of current asthma can occur because of physicians' failure to confirm airflow limitation at the time of diagnosis, and when sustained remission of disease goes unrecognized. In this review, we define under and over-diagnosis and explore the prevalence and burden of under and over-diagnosis of asthma in both patients and within health care systems. We further describe potential solutions to prevent under and over-diagnosis of asthma.
Article
Background: Mexican-born children living in the United States have a lower prevalence of asthma than other US children. Although children of Mexican descent near the Arizona (AZ)-Sonora border are genetically similar, differences in environmental exposures might result in differences in asthma prevalence across this region. Objective: The objective of this study was to determine if the prevalence of asthma and wheeze in these children varies across the AZ-Sonora border. Methods: The International Study of Asthma and Allergy in Children written and video questionnaires were administered to 1753 adolescents from 5 middle schools: Tucson (school A), Nogales, AZ (schools B, C), and Nogales, Sonora, Mexico (schools D, E). The prevalence of asthma and symptoms was compared, with analyses in the AZ schools limited to self-identified Mexican American students. Results: Compared with the Sonoran reference school E, the adjusted odds ratio (OR) for asthma was significantly higher in US schools A (OR 4.89, 95% confidence interval [CI] 2.72-8.80), B (OR 3.47, 95% CI 1.88-6.42), and C (OR 4.12, 95% CI 1.78-9.60). The adjusted OR for wheeze in the past year was significantly higher in schools A (OR 2.19, 95% CI 1.20-4.01) and B (OR 2.67, 95% CI 1.42-5.01) on the written questionnaire and significantly higher in A (OR 2.13, 95% CI 1.22-3.75), B (OR 1.95, 95% CI 1.07-3.53), and Sonoran school D (OR 2.34, 95% CI 1.28-4.30) on the video questionnaire compared with school E. Conclusions: Asthma and wheeze prevalence differed significantly between schools and was higher in the United States. Environmental factors that may account for these differences could provide insight into mechanisms of protection from asthma.