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The SUN cohort study (Seguimiento University of Navarra)

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Cohort study (the SUN project) to identify dietary determinants of hypertension, diabetes, obesity and coronary heart disease (CHD), among other conditions. The SUN project is a Mediterranean dynamic prospective follow-up (cohort) study assessing participants every 2 years. The recruitment started in 2000 and it is permanently open (this is a dynamic cohort). A preliminary case-control study of myocardial infarction was also conducted, selecting incident cases of myocardial infarction and matched hospital controls. The SUN study is conducted in Spain with university graduates, most of them being former students of the University of Navarra. The case-control study was conducted in three tertiary hospitals in the city of Pamplona (Spain). The case-control study included 171 cases and 171 controls. We have currently enrolled more than 17,500 participants in the SUN cohort. Approximately 7500 of them were enrolled less than 2 years ago, and have not received yet the invitation to complete the 2-year follow-up assessment. The follow-up rate for the first 10,000 participants approaches 90%. The case-control study found inverse associations between olive oil (or adherence to a Mediterranean food pattern) and myocardial infarction. In the SUN cohort, after 28.5 months of follow-up a higher adherence to a Mediterranean food pattern rich in olive oil was associated with a reduced risk of hypertension, though the results were statistically significant only among men. The SUN study and the accompanying case-control study support the benefits of a Mediterranean diet and olive oil against CHD and hypertension.
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The SUN cohort study (Seguimiento University of Navarra)
Miguel A
´
ngel Martı
´
nez-Gonza
´
lez*
Department of Preventive Medicine and Public Health, Facultad de Medicina, Clı
´
nica Universitaria, Universidad de
Navarra, Irunlarrea 1, 31080 Pamplona, Spain
Abstract
Objective: Cohort study (the SUN project) to identify dietary determinants of
hypertension, diabetes, obesity and coronary heart disease (CHD), among other
conditions.
Design: The SUN project is a Mediterranean dynamic prospective follow-up (cohort)
study assessing participants every 2 years. The recruitment started in 2000 and it is
permanently open (this is a dynamic cohort). A preliminary casecontrol study of
myocardial infarction was also conducted, selecting incident cases of myocardial
infarction and matched hospital controls.
Setting: The SUN study is conducted in Spain with university graduates, most of them
being former students of the University of Navarra. The casecontrol study was
conducted in three tertiary hospitals in the city of Pamplona (Spain).
Subjects: The casecontrol study included 171 cases and 171 controls. We have
currently enrolled more than 17 500 participants in the SUN cohort. Approximately
7500 of them were enrolled less than 2 years ago, and have not received yet the
invitation to complete the 2-year follow-up assessment. The follow-up rate for the first
10 000 participants approaches 90%.
Results: The casecontrol study found inverse associations between olive oil (or
adherence to a Mediterranean food pattern) and myocardial infarction. In the SUN
cohort, after 28.5 months of follow-up a higher adherence to a Mediterranean food
pattern rich in olive oil was associated with a reduced risk of hypertension, though
the results were statistically significant only among men.
Conclusions: The SUN study and the accompanying casecontrol study support the
benefits of a Mediterranean diet and olive oil against CHD and hypertension.
Keywords
Monounsaturated fatty acids
Hypertension
Coronary heart disease
Longitudinal studies
Mediterranean diet
Olive oil
Follow-up
Food items contain hundreds of chemical components
that tend to be interrelated, thus making the study of their
relationship with health outcomes particularly difficult.
Therefore, the task of assessing the effect of food patterns
on health is much more difficult than that of other
exposures usually assessed in epidemiology. Dietary
habits may be described according to the intake of
nutrients, in terms of specific foods or food groups or in
terms of overall food patterns. In general, the maximum
information will be obtained when the analyses are based
on all approaches
1,2
. Nutritional epidemiology began
studying the effect of specific nutrients mainly defined
from a biochemical point of view. Thus, the classical
analytical approach was to assess the exposure to single
nutrients or isolated food items, whereas a growing
interest exists nowadays in studying overall food patterns
because food items and nutrients could have synergistic or
antagonistic effects when they are consumed in combi-
nation
3–5
. Overall patterns do represent the current
practices found in the assessed population and, therefore,
provide useful epidemiological information. Therefore,
the assessment of the exposure to a particular existing
food pattern in the real world may provide a direct and
real base for elaborating food guidelines. In addition, this
approach overcomes the problems between nutrient
correlations. For example, it is very usual to find a
substantial inverse correlation between fibre intake and
saturated fatty acids (SFA), and the single-nutrient
approach would not allow to ascertain whether there is
a protection against coronary heart disease (CHD)
afforded by fibre or a harm due to SFA intake. In this
context, the Mediterranean food pattern has attracted
considerable interest because of the belief that it may
provide a substantial reduction in CHD risk
6
.
Most information suggesting substantial benefits of the
Mediterranean food pattern on cardiovascular risk comes
from casecontrol studies, which are specially vulnerable
to recall bias and selection biases, as may result from
differential participation of cases and controls, selective
survival of participating cases, and selection of a diet-
related disease for the control group. Large cohort studies
with repeated dietary assessment can give the most
definitive answers. Unless similar cohorts are started now
in Southern Europe, the needed evidences to produce
q The Author 2006*Corresponding author: Email mamartinez@unav.es
Public Health Nutrition: 9(1A), 127–131
DOI: 10.1079/PHN2005935
soundly based guidelines will probably still remain
controversial in the next 1020 years. A large cohort
study on diet and cancer, the European Prospective
Investigation into Cancer and Nutrition (EPIC) was started
in several European countries during the 1990s. However,
it was not specifically designed to study the Mediterranean
diet, nor has it selected a population which can be easily
tracked for morbidity endpoints different from cancer
because the follow-up in the EPIC study is based on cancer
registries. A follow-up is planned only for fatal cardiovas-
cular diseases (EPIC-Heart).
The most useful information available in public health
about cardiovascular disease comes from cohorts which
selected populations living in stable towns (Framingham),
former students of a particular university (Harvard
alumni), or highly educated professionals (Nurses’ Health
Study, Health Professionals’ Follow-up Study). They have
achieved an almost complete follow-up for fatal and non-
fatal cases. The experience shows that these studies are
invaluable. Nevertheless, a Mediterranean dietary pattern
is uncommon in these US populations. For example,
although increasing, olive consumption is still low, and the
main source of monounsaturated fatty acids (MUFA) is red
meat; the main source of ethanol intake is beer and
liquors, instead of wine; and the main sources of some
micronutrients are vitamin supplements instead of natural
fresh fruits and vegetables. The only large available
Mediterranean nutritional follow-up study is the Greek
cohort of the EPIC study
7
. It has assessed only fatal cases of
CHD (54 cases observed in 22 043 participants followed-
up during 44 months). Using mortality as an endpoint can
be confounded by factors related to case-fatality rate.
Therefore, no available evidence about the association of a
Mediterranean food pattern and the incidence of CHD
(including both fatal and non-fatal) cases exists. Large
cohorts assessing the incidence of CHD and other
common diseases are needed. The Mediterranean food
pattern has been many times postulated as a healthful
alternative to reduce cardiovascular risk. Nevertheless, it is
difficult to understand why a large cohort study with these
characteristics has never been conducted in any Medi-
terranean country.
This SUN (Seguimiento Universidad de Navarra) project
is developing a large long-term prospective study of
dietary determinants of CHD, diabetes, and hypertension
among Spanish subjects.
The SUN study: background, design and methods
The sharp contrast in dietary habits between the USA and
Spain provides an exceptional opportunity to assess what
aspects of the Mediterranean food pattern may be
protective. That is the reason why we decided to start a
prospective follow-up study (the SUN cohort) based on
mailed questionnaires sent to alumni of the University of
Navarra every 2 years.
We follow the design of a dynamic cohort, in which the
recruitment of new participants is permanently open.
We are inviting to participate all Spanish alumni of the
University of Navarra and several other professional
collectives with a university degree (Table 1 shows the
cumulative number of participants). We select only those
university graduates who are willing to commit themselves
for returning questionnaires every 2 years. A semi-
quantitative food-frequency questionnaire previously
validated in Spain
8
is used together with other ques-
tionnaires designed to collect lifestyle characteristics.
University graduates have the advantage of possessing a
high cultural level that helps them to better understand
and answer mailed questionnaires.
The SUN study was approved by the Institutional
Review Board of the University of Navarra. Among its
objectives are the study of the association between dietary
and other lifestyle variables and the incidence of
cardiovascular disease, hypertension, obesity, and dia-
betes
9–12
. Beginning on December 1999, all university
graduates from the University of Navarra, and university
graduates from professional associations, received a letter
of invitation to participate in the study, a questionnaire to
respond and a postage-prepaid envelope to return the
questionnaire. This baseline questionnaire gathered
information about sociodemographic variables, lifestyle
factors, clinical variables and included a detailed food-
frequency questionnaire
8
. A pilot study was conducted in
1999
10
. Currently, up to November 2005, more than 17 500
participants have been recruited and have completed the
baseline assessment. Some of them (approximately 7500)
were enrolled less than 2 years ago, and, therefore, they
have not received yet the invitation to answer the 2-year
follow-up questionnaire. The follow-up rate for the first
10 000 participants who have been already included in the
cohort for a longer period than 2 years approaches 90%.
In cross-sectional analyses of the baseline data of our
first participants, we identified those factors associated to a
higher adherence to a Mediterranean food pattern
11,12
.We
also conducted an analysis to identify the respective role
of MUFA and fruit/vegetable consumption in the
prevalence of high blood pressure
13
. In addition, a
previous case control study of first non-fatal myocardial
Table 1 Cumulative number of participants in the SUN cohort
study
Year 2000 2001 2002 2003 2004 2005
Total (cumulative)
number of enrolled
participants
4717 8012 11 664 12 493 16 183 17 813
The recruitment of the cohort is permanently open (this is a dynamic
cohort).
The cumulative number of participants for each year corresponds to 31
December of each year, with the exception of 2005 that corresponds to 15
October.
MA
´
Martı
´
nez-Gonza
´
lez128
infarction (MI) (see below) was conducted using the same
dietary assessment tool that we are currently using in the
cohort study
14 22
.
Preliminary casecontrol study of Mediterranean
diet and MI
We conducted a casecontrol study in three tertiary
hospitals of Pamplona, Spain, between 1999 and 2001.
Study physicians enrolled 171 patients younger than 80
years of age with a first non-fatal MI and 171 control
patients matched by age, sex, hospital and calendar
month. We excluded patients with any prior major
cardiovascular disease. Participants were interviewed
about medical factors and lifestyle and completed the
same food-frequency questionnaire previously validated
in Spain that we are using in the SUN cohort
8
. Cases were
defined as women and men less than 80 years of age with a
first MI (International Classification of Diseases code 410)
admitted to one of the three tertiary hospitals of Pamplona,
Spain, within the period October 1999 through February
2001. For inclusion in the study, patients had to fulfil the
criteria for definite MI of the MONICA project (two or
more electrocardiograms showing definitive changes,
electrocardiograms showing probable changes plus
abnormal cardiac enzymes, or typical symptoms plus
abnormal enzymes). We excluded patients with previous
history of angina pectoris, a previous diagnosis of CHD, or
other prior diagnosis of major cardiovascular disease.
Participation rate was 95%. Institutional Review Board
approval was obtained from the Navarre Medical School,
and patients provided informed consent before
participation.
Eligible controls were patients admitted to surgery,
trauma, or urology wards of the same hospitals for
treatment of conditions believed to be unrelated to diet.
We applied the same exclusion criteria for controls as for
cases. We matched one control to each case by age (within
5 years), sex, calendar time (hospitalised during the same
month), and hospital. Eight controls refused to participate;
each was replaced by another patient of similar
characteristics for matching variables.
The same physician who interviewed a case patient also
interviewed the respective matched control. The physician
clarified any questions the patient might have had in
completing the questionnaire and subsequently con-
ducted a face-to-face interview about coronary risk factors
(i.e. smoking, diabetes, high blood pressure, high blood
cholesterol, and recent weight changes) and family history
of cardiovascular disease. The physician took systolic and
fifth-phase diastolic blood pressure readings and
measured weight and height. In the food-frequency
questionnaire, nine options for frequency of consumption
were possible. The type of fat used in frying was
specifically assessed. A dietician updated the nutrient
databank using the latest available information included in
the food composition tables for Spain. Participants were
asked to report their usual time spent practising the
following activities: walking, jogging, running, athletics,
cycling, swimming, racquet sports, soccer, team sports
other than soccer, dancing, aerobics, hiking, climbing,
gardening, skiing, skating, fishing, martial arts, and water
sports. To quantify the volume and intensity of leisure-
time physical activity, we computed an activity metabolic
equivalent (MET)
23 25
.
We report below the most salient findings of this case
control study. Odds ratios (OR) and 95% confidence
intervals (CI) were estimated for MI using conditional
logistic regression with 171 casecontrol matched pairs.
We assumed that OR from this casecontrol study provide
a valid estimate of the relative risk. Energy-adjusted
intakes were computed using the residuals method
1
.We
adjusted relative risks for well-established risk factors for
MI, including dietary exposures.
Olive oil and MI
The exposure to the upper quintile of energy-adjusted
olive oil (median intake: 54 g/day) was associated with a
statistically significant 82% relative reduction in the risk of
a first MI (OR ¼ 0.18, 95% CI 0.060.63) after adjustment
for dietary and non-dietary confounders. These data
suggest that olive oil may reduce the risk of CHD
14
. Our
findings were consistent with the subsequent report of the
GISSI cohort, where the outcome was restricted only to
fatal cases
22
. Further large cohort studies with non-fatal
events as outcome and randomised trials are still needed
to confirm our findings
2,6
.
Mediterranean dietary pattern and MI
We defined a Mediterranean food pattern including six
food items that we considered protective: (1) olive oil, (2)
fibre, (3) fruits, (4) vegetables, (5) fish, and (6) alcohol. For
each of these six dietary factors, we calculated the
distribution according to quintiles within the study and
assigned each participant a score of 15 corresponding to
the quintile of intake, with 1 representing the lowest and 5
representing the highest quintile. We also estimated the
quintiles of two other elements assumed to be associated
with a higher risk: (7) meat/meat products, and (8) some
items with high glycaemic load (white bread, pasta and
rice). For these two elements we inversely ranked the
score, with 1 representing the highest and 5 representing
the lowest quintile. Finally, we summed up the eight
quintile values for each participant. We found that the
higher the score, the lower the odds of MI. A significant
linear trend was apparent after adjustment for the
main cardiovascular risk factors. For each additional
point in the Mediterranean pattern (observed range 938)
the OR (95% CI) was 0.92 (0.860.98). Our data support
the hypothesis that a Mediterranean food pattern (that
emphasises olive oil, fibre, fruits, vegetables, fish and
alcohol, and reduces meat/meat products) can be an
effective measure for reducing the risk of MI. However,
The SUN cohort study 129
our results support the exclusion of refined cereals
with a high glycaemic load as healthy elements of this
pattern
17
.
Subsequent reports from case control studies and the
Greek EPIC cohort are consistent with these results
7,26
.
Olive oil and reduced risk of hypertension among
men
A major goal of dietary recommendations is to reduce
blood pressure. In early epidemiological studies, mainly
conducted in the United States, MUFA showed a
deleterious association with blood pressure, or no
relationship at all. However, more recent studies,
conducted in Mediterranean countries, have shed new
light on this issue
27
. It is conceivable that the lower blood
pressure levels and the relatively lower prevalence of
hypertension found in Spain, in spite of a high average
alcohol consumption, may be explained by a high
consumption of olive oil. Based in an increasing amount
of evidence, the classical Mediterranean food pattern has
been proposed as a healthy choice for the prevention of
cardiovascular disease
28
. Part of its beneficial impact can
be mediated through a favorable effect on blood pressure.
A major characteristic of Mediterranean diet is a high
supply of energy coming from MUFA, mainly from olive
oil. When olive oil is the major dietary source of
monounsaturated fat, as it happens in Mediterranean
countries, it could exert a favorable effect on blood
pressure. We tested this hypothesis using a prospective
design in the SUN cohort.
The retention proportion for the first 7650 participants
in the SUN cohort was 90%. The median follow-up time
was 28.5 months. Out the first 6863 participants in our
cohort with data at baseline and at the first follow-up
questionnaire (after . 2-year follow-up), 658 were
excluded due to prevalent hypertension at baseline and
632 because of extremely low or high caloric intakes
(, 400 kcal/day for women, , 600 kcal/day for men,
. 3500 kcal/day for women, . 4200 kcal/day for men).
Finally, 5573 participants were available for analysis, 3384
women and 2189 men. We assessed the validity of a self-
reported diagnosis of hypertension in a sample of 79
individuals reporting a medical diagnosis of hypertension
and 41 not reporting such diagnosis. The positive and
negative predictive values for the self-reported diagnosis
of hypertension were 82 and 85%, respectively
29
.
During follow-up, 161 incident cases of hypertension
were identified among them (cumulative incidence 2.9%).
The incidence was much lower in women than in men (1.7
vs. 4.7%). The cumulative incidence of hypertension was
computed for each quintile of olive oil consumption. To
avoid confounding for other variables simultaneously
associated with the outcome (hypertension) and the main
exposure, we used non-conditional logistic regression
modelling after adjusting for age, gender, body mass
index, physical activity during leisure time, total energy
intake, alcohol consumption, sodium intake, and calcium
intake. In addition, models for each gender were run
separately. Tests for a linear trend in the relationship
between olive oil consumption and risk of hypertension
were obtained by assigning the median value for each
quintile of olive oil consumption and modeling this
variable as continuous in the logistic model.
The risk of developing hypertension during follow-up
was lower among participants with a higher baseline
consumption of olive oil, but the results were not
statistically significant (P ¼ 0.13 for the trend test).
Considering men and women together, the adjusted OR
(95% CI) of hypertension for the two upper quintiles of
olive oil consumption (compared with the first quintile)
were 0.55 (0.310.98) for the fourth quintile and 0.63
(0.361.07) for the fifth quintile. Among men, the adjusted
OR (95% CI) of hypertension for the second to fifth
quintiles of olive oil consumption were 0.55 (0.281.10),
0.75 (0.391.43), 0.32 (0.150.70), and 0.46 (0.230.94),
respectively. The linear trend test was statistically
significant only in men. No association was found
between olive oil consumption and the risk of hyperten-
sion in women
30
.
Our results are consistent with a cross-sectional analysis
conducted in Greece
31
, with the results of a small trial
conducted in Italy
32
and with the recent results from the
OmniHeart Randomized Trial
33
, and they support a
protection afforded by olive oil against the risk of
developing hypertension.
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the American Medical Association 2005; 294: 245564.
The SUN cohort study 131
... To overcome the research gap of investigating the generalizability of DP-T2D associations using the approach of simplified DPs, the present study aimed 1) to investigate the association of previously reported T2D-associated DPs [1] with incident T2D and 2) to evaluate, if two DPs of overlapping FGs ("mainly healthy" and "mainly unhealthy"), also previously identified in the same systematic review [1], are associated with incident T2D. For this purpose, the InterConnect collaboration project offers a well-suited research platform for federated meta-analyses of harmonized individual level study data from 25 cohorts [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] across different continents and adjusting for a common set of potential confounders across studies [34][35][36]. As another advantage, this approach allowed the inclusion of cohorts that have relevant data, but never published on the topic before. ...
... eu/ data-disco very/) and literature was screened to identify cohorts with suitable data like study populations representing the general population without prevalent T2D, dietary intake information (amount, frequency), incident T2D as outcome (self-report, objective measures), and information on the covariates age, sex, smoking, body mass index (BMI), waist circumference or waist-hip ratio, physical activity, alcohol consumption, education or occupation, family history of diabetes, other health exposures (cardiovascular diseases, history of previous illness). Of 103 identified cohorts, 25 collaborating cohorts (Table S1) contributed data to this project [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]37]. The Zutphen Elderly study also contributed data, but was excluded due to a too low number of cases [37]. ...
... Other reasons for non-participation (Fig. S1) were failed contact (n = 46), no interest in research question (n = 10), insufficient data (n = 15) or no study capacity (n = 6). The collaborating cohorts [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]38] included 13 cohorts from Europe, eight from the Americas (North and South America), three from Western Pacific (Australia, Republic of Korea), and one from the Eastern Mediterranean (Iran). All cohorts obtained ethical review board approval at the host institution and informed consent from participants. ...
Article
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Purpose In several studies, exploratory dietary patterns (DP), derived by principal component analysis, were inversely or positively associated with incident type 2 diabetes (T2D). However, findings remained study-specific, inconsistent and rarely replicated. This study aimed to investigate the associations between DPs and T2D in multiple cohorts across the world. Methods This federated meta-analysis of individual participant data was based on 25 prospective cohort studies from 5 continents including a total of 390,664 participants with a follow-up for T2D (3.8–25.0 years). After data harmonization across cohorts we evaluated 15 previously identified T2D-related DPs for association with incident T2D estimating pooled incidence rate ratios (IRR) and confidence intervals (CI) by Piecewise Poisson regression and random-effects meta-analysis. Results 29,386 participants developed T2D during follow-up. Five DPs, characterized by higher intake of red meat, processed meat, French fries and refined grains, were associated with higher incidence of T2D. The strongest association was observed for a DP comprising these food groups besides others (IRR pooled per 1 SD = 1.104, 95% CI 1.059–1.151). Although heterogeneity was present ( I ² = 85%), IRR exceeded 1 in 18 of the 20 meta-analyzed studies. Original DPs associated with lower T2D risk were not confirmed. Instead, a healthy DP (HDP1) was associated with higher T2D risk (IRR pooled per 1 SD = 1.057, 95% CI 1.027–1.088). Conclusion Our findings from various cohorts revealed positive associations for several DPs, characterized by higher intake of red meat, processed meat, French fries and refined grains, adding to the evidence-base that links DPs to higher T2D risk. However, no inverse DP–T2D associations were confirmed.
... Participants are university graduates from many different universities all over Spain. The methods and more specific details of the SUN cohort have already been described previously (40). ...
Article
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Adherence to the traditional Mediterranean diet has been customarily assessed with the Mediterranean diet score (MDS or Trichopolou Index), with values of 0 or 1 assigned to each of the nine elements, and with the use of the sex-specific median as the cutoff. The value of persons whose consumption of the six beneficial items (ratio of monounsaturated to saturated fatty acids, vegetables, legumes, fruits and nuts, cereal, and fish) is at or above the median and is assigned a value of 1. Otherwise they receive 0 points. For detrimental elements (meats and dairy products) persons whose consumption is below the median are assigned a value of 1. An additional ninth point is assigned to moderate ethanol intake. We assessed the effect of each of the nine components of the MDS (replacing the fats ratio with olive oil, the main source of monounsaturated fats in the Mediterranean diet) on the risk of COVID-19 infection, symptomatic and severe COVID-19. From March to December 2020, 9,699 participants of the “Seguimiento Universidad de Navarra” (SUN) cohort answered a COVID-19 questionnaire. After excluding doctors and nurses, 5,194 participants were included in the main statistical analyses. Among them, we observed 382 cases of COVID-19 based on symptoms and clinical diagnosis; 167 of them with test confirmation. For the two COVID-19 definitions used, we found a significant decrease in risk for a higher adherence to the Mediterranean diet (OR = 0.64, 95% CI: 0.42–0.98, p for trend = 0.040; and OR = 0.44, 95% CI: 0.22–0.88, p for trend = 0.020, for test-diagnosed cases). A protective effect was also found for symptomatic COVID-19 (OR = 0.64, 95% CI: 0.41–1.00, p for trend = 0.050). Among the different individual food groups, only the consumption of whole dairy products showed a harmful direct association. The Mediterranean diet as a whole seems more important than each of its components in preventing the infection and symptoms of COVID-19.
... In the United States, 2 university cohorts were established at Harvard University to investigate risk factors for chronic diseases and long-term health in nurses and health professionals [6,7]. In Spain, a prospective university graduate cohort was established at Seguimiento Universidad de Navarra (SUN) to examine dietary habits in the Mediterranean region [8,9]. The scope of the SUN study was subsequently broadened to examine other risk factors and health conditions and expanded to include graduates from 5 other Spanish universities [9]. ...
Article
Background Emerging adulthood is a distinct segment of an individual’s life course. The defining features of this transitional period include identity exploration, instability, future possibilities, self-focus, and feeling in-between, all of which are thought to affect quality of life, health, and well-being. A longitudinal cohort study with a comprehensive set of measures would be a valuable resource for improving the understanding of the multifaceted elements and unique challenges that contribute to the health and well-being of emerging adults. Objective The main aim of this pilot study was to evaluate the feasibility and acceptability of recruiting university graduates to establish a longitudinal cohort study to inform the understanding of emerging adulthood. Methods This pilot study was conducted among graduates at a large university. It involved collecting web-based survey data at baseline (ie, graduation) and 12 months post baseline, and linking survey responses to health records from administrative data collections. The feasibility outcome measures of interest included the recruitment rate, response rate, retention rate, data linkage opt-out rate, and availability of linked health records. Descriptive statistics were used to evaluate the representativeness of the sample, completeness of the survey responses, and data linkage characteristics. Results Only 2.8% of invited graduates (238/8532) agreed to participate in this pilot cohort study, of whom 59.7% (142/238) responded to the baseline survey. The retention rate between the baseline and follow-up surveys was 69.7% (99/142). The completeness of the surveys was excellent, with the proportion of answered questions in each survey domain ranging from 87.3% to 100% in both the baseline and follow-up surveys. The data linkage opt-out rate was 32.4% (77/238). Conclusions The overall recruitment rate was poor, while the completeness of survey responses among respondents ranged from good to excellent. There was reasonable acceptability for conducting data linkage of health records from administrative data collections and survey responses. This pilot study offers insights and recommendations for future research aiming to establish a longitudinal cohort study to investigate health and well-being in emerging adults. Trial Registration Australian New Zealand Clinical Trials Registry number ACTRN12618001364268; https://tinyurl.com/teec8wh International Registered Report Identifier (IRRID) RR2-10.2196/16108
... Several strengths characterize the present study, including the prospective design, the large sample size with a >90% retention rate [66], the long follow-up, and the use of a FFQ that has been repeatedly validated in Spain [25][26][27]. In addition, we were able to control for several confounders, including family history of diabetes, nutritional status, and potential lifestyle and demographic confounders. ...
Article
Full-text available
We aimed to investigate the relationship between the pre-gestational consumption of ultra-processed foods (UPF) and the risk of gestational diabetes (GDM). We carried out a prospective study among 3730 Spanish women of the SUN cohort who reported at least one pregnancy after baseline recruitment. Cases of GDM were identified among women with a confirmed diagnosis of GDM. UPF consumption was assessed through a validated, semi-quantitative food frequency questionnaire and the frequency of UPF consumption was categorized in tertiles. We identified 186 cases of GDM. In the pooled sample, we did not observe a significant association of UPF with the risk of GDM. When we stratified by age, the multivariate OR for the third tertile of UPF consumption compared with the lowest one was 2.05 (95% CI 1.03, 4.07) in women aged ≥30 years at baseline (Ptrend = 0.041). The association remained significant in a sensitivity analysis after changing many of our assumptions and adjusting for additional confounders. No association between a higher UPF consumption and GDM risk was observed in women aged 18–29 years. The pre-gestational UPF consumption may be a risk factor for GDM, especially in women aged 30 years or more. Confirmatory studies are needed to validate these findings.
... Participants are university graduates from all over Spain. The methods and many specific details of the SUN cohort have already been described [15]. ...
Article
Background & aims A potential protection against COVID-19 infection by a high-quality dietary pattern is to be expected given the biological plausibility supporting the beneficial effects of adequate nutrition on the immune system. However, knowledge on the relationship between long-term maintained healthy dietary patterns, such as the Mediterranean diet, and the risk of SARS-2-Cov infection is still sparse. We longitudinally assessed this association in a well-known Mediterranean cohort. Methods We assessed 9677 participants from the SUN Project, a prospective cohort of middle-aged university graduates in Spain. We inquired about a positive result in a COVID-19 diagnostic test during the months of February to December 2020. After excluding health professionals (HP), 5194 participants were included in the statistical analyses (mean age: 52.6, SD: 12.4; 55.2% women). Food habits were assessed at baseline using a previously validated semiquantitative 136-item food frequency questionnaire. Adherence to the Mediterranean diet (cumulative average of 2 repeated measurements separated 10 years apart) was assessed using the 0-to-9 Mediterranean Diet Score (MDS). We used multivariable logistic regression models to estimate odds ratios and 95% confidence intervals for incident COVID-19 according to the MDS. Results Among 5194 non-HP participants, 122 reported to have received a diagnosis of COVID-19 based on a specific diagnostic test. Participants with intermediate adherence to the Mediterranean diet (MDS ≥4 & <7) had a significantly lower odds of developing COVID-19 (multivariable-adjusted OR = 0.50, 95% CI, 0.34–0.73), and those with the highest adherence (MDS ≥ 7) exhibited the lowest risk (multivariable-adjusted OR = 0.36, 0.16–0.84, p for trend < 0.001) as compared with participants with MDS ≤3. This inverse association remained robust within subgroups and in sensitivity analyses. Notwithstanding, no significant associations were observed for health professionals (p for interaction = 0.06). Conclusion In conclusion, better adherence to the Mediterranean diet may be associated with a lower risk of COVID-19. Our results are applicable only to persons who are not health professionals.
... In particular, studies in humans have shown that EVOO decreases blood pressure, with an inverse relationship to EVOO consumption. This beneficial effect has been attributed to EVOO's high levels of monounsaturated fatty acids (MUFA) and phenol components, which are absent among various cooking oils [5][6][7]. ...
Article
Full-text available
Accumulating evidence has shown the beneficial health effects of extra virgin olive oil (EVOO) consumption in reducing blood pressure and preventing the risk of developing hypertension. Some studies associate the hypotensive activity of EVOO to a minor component-the phenols. This study was designed to investigate the effects of EVOO phenols on the rat resistance mesenteric artery (MA) and to find out the possible vascular pathways involved. The experiments were carried out using a pressurized myograph, which allowed the effects of phenols on isolated MA to be tested under different conditions: (a) with endothelium removed; (b) with inhibition of nitric oxide synthase by Nω-Nitro-l-arginine methyl ester hydrochloride (l-NAME, 10-4 M) + Nω-Nitro-l-arginine (l-NNA, 10-4 M) ; (c) with inhibition of cyclooxygenase by indomethacin (10-5 M); (d) with inhibition of guanylate cyclase by 1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one (ODQ,10-5 M) or adenylate cyclase by 9-(Tetrahydro-2'-furyl)adenine (SQ, 10-5 M); (e) with depolarization by high potassium chloride (40 mM); and (f) with inhibition of the large conductance Ca2+-potassium channels (BKCa2+) with paxilline (10-5 M). EVOO phenols induce vasodilation of the endothelium, mediated by a direct effect on smooth muscle cells (SMC) by activation of BKCa2+ channels, an action by which phenols can regulate the vascular tone of the resistance artery. Phenols can be regarded as bioactive molecules that may contribute to the antihypertensive effects of EVOO.
Article
Background Myopia is a highly prevalent disorder, and one of the first causes of blindness. In turn, alcohol consumption has been shown to be a risk factor for many diseases and a main contributor to the global burden of disease. However, no studies have investigated the relationship between alcohol intake and myopia. Our aim was to prospectively assess the association between alcohol intake and the development or progression of myopia. Methods In a Spanish dynamic prospective cohort (the SUN Project) we assessed 15,642 university graduates, recruited between 1999-2018 and followed up biennially through mailed questionnaires. Alcohol intake was assessed with a validated 136-item food frequency questionnaire. Development or progression of myopia was collected in subsequent questionnaires during follow-up every two years. Results Alcohol intake was linearly and significantly associated with a higher risk of myopia development or progression: the OR for 10-year incidence/progression of myopia was 1.05, 95% CI 1.01-1.09 per each 10-grams increase in alcohol intake. Conclusions Alcohol consumption might lead to the development or progression of myopia, although confirmation is needed for the mechanisms through which this association may occur, thus further research is needed to verify these findings.
Article
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Background A potential relationship between depression and the intake of dietary fiber has been hypothesized in several studies. However, no meta-analysis has been conducted so far to explore the association between these two variables. Hence, we designed the present meta-analysis to elucidate the relationship between the intake of dietary fiber and depression. Methods A comprehensive search was performed using the PubMed/Medline, Scopus, Web of Science and Google Scholar databases to identify any relevant studies published from inception to October 2019. Observational studies (cross-sectional and case-control) were included in the analysis. Results Pooled analysis from the random-effects model of four case-control studies revealed that the consumption of dietary fiber in patients with depression was significantly lower versus healthy controls (WMD: -1.41 mg/dl, 95% CI: -2.32, -0.51, P = 0.002). No significant heterogeneity was demonstrated among the analyzed studies (I2 = 4.0%, P = 0.37). By pooling 5 effect sizes of cross-sectional studies (with a total of 97023 subjects), we demonstrated that a higher dietary consumption of fiber was associated with significantly lower odds of depression (OR = 0.76; 95% CI: 0.64, 0.90; P = 0.010), with a low heterogeneity seen among the retrieved studies (I2 = 43.9%; P = 0.12). Conclusion An increased intake of total dietary fiber is associated with lower odds of depression. Further studies are needed to evaluate the relationship between the different types of dietary fiber and depression.
Article
Background: Severe cognitive decline is one of the major public health problems in developed countries. Finding modifiable risk factors could become essential to develop strategies to prevent or delay dementia progression and stop its rising incidence. Objective: Our aim was to investigate the association between hypertension and cognitive function and to assess whether better adherence to the Mediterranean diet may modify this association. Methods: A subsample of 764 participants from the ‘Seguimiento Universidad de Navarra’ (SUN) cohort older than 55 years was evaluated with the Spanish Telephone Interview for Cognitive Status (TICS-m) at two-time points, separated by 6 years. Multivariable-adjusted linear regression models were used to prospectively assess the association between hypertension –also according to adherence to the Mediterranean diet– and 6-y changes in cognitive function. Results: The adjusted between-group difference in the 6-year change of the TICS-m score between hypertensive participants and their non-hypertensive counterparts was −0.36 (95% CI −0.70, −0.02). This association was stronger among participants with a lower adherence to the Mediterranean diet [−0.62 (95% CI: −1.09, −0.15)] but the differences between hypertensive and non-hypertensive participants were no longer significant among participants with a higher baseline adherence to the Mediterranean diet. Conclusion: In this Mediterranean cohort, hypertension was inversely associated with cognitive function, but an attenuation of this detrimental association by a moderate/high adherence to the Mediterranean diet was suggested.
Article
Background: The association of dietary pattern with the risk of basal cell carcinoma (BCC) is little understood and has scarcely been investigated. Objectives: We assessed the association of several complete dietary patterns [Mediterranean, Dietary Approaches to Stop Hypertension (DASH), and Pro-vegetarian dietary pattern] with the risk of BCC, conducting a nested case-control study (4 controls for each case). Methods: Cases and controls were selected from the SUN (Seguimiento Universidad de Navarra) cohort using risk set sampling. Cases were identified among subjects free of skin cancer at baseline but who later reported a physician-made BCC diagnosis during the follow-up period. In the cohort we identified 101 incident cases of BCC. Results: In multivariable-adjusted conditional logistic regression analyses, better adherence to the Mediterranean diet (highest compared with lowest quintile) was associated with a 72% relative reduction in the odds of BCC (OR: 0.28; 95% CI: 0.10, 0.77; Ptrend = 0.014); the DASH diet was associated with a 68% RR reduction (OR: 0.32; 95% CI: 0.14, 0.76; Ptrend = 0.013) for the comparison between extreme quintiles. No association was found between a Pro-vegetarian dietary pattern and BCC. Higher fruit consumption (highest compared with lowest quintile, OR: 0.27; 95% CI: 0.11, 0.64; Ptrend < 0.001) and low-fat dairy products (OR: 0.39; 95% CI: 0.16, 0.92; Ptrend = 0.014) were associated with a lower BCC risk. Conclusions: Our results suggest that Mediterranean and DASH dietary patterns may be associated with a lower risk of BCC, but confirmatory studies are required.
Article
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Resumen Fundamento: La dieta mediterránea ha sido propuesta como modelo de patrón dietético para la prevención de la cardiopatía isquémica. El proyecto SUN ("Seguimiento Universidad de Navarra") es un estudio epidemiológico prospectivo de cohortes, que se inició en el año 2000 y que va dirigido a identificar determinantes dietéticos y no dietéticos implicados en estas enfermedades. La viabilidad del proyecto, se comprobó con un estudio piloto en dos fases. Métodos: La primera fase del estudio piloto contó con la participa-ción de voluntarios en los que se valoraron las exposiciones dietéti-cas y no dietéticas mediante un cuestionario autoadministrado y por entrevista personal. Para la segunda fase, se seleccionó una muestra aleatoria de 600 graduados y se les envió el cuestionario por correo. Para estimar la variabilidad inter-sujetos se calcularon los percentiles 10, 25, 50, 75 y 90 de consumo para los principales alimentos y nutrientes considerados. Resultados: Los participantes entendieron y respondieron adecua-damente los cuestionarios. El tiempo medio empleado en contestar el cuestionario fue de 55,0 minutos (IC 95%=50,7-59,3). Se encon-tró una amplia variabilidad inter-sujetos entre los percentiles 10 y 90 en el consumo de los principales alimentos que pueden conside-rarse indicadores de la dieta mediterránea, como son el aceite de oliva, las frutas, las verduras y el vino. Conclusiones: La submuestra presentó una participación relativa-mente aceptable. Se halló un patrón de dieta mediterránea con una variabilidad inter-sujetos suficientemente amplia como para poder encontrar asociaciones entre el consumo de alimentos y la incidencia de las principales enfermedades cardiovasculares. Summary Background: The Mediterranean diet has been postulated as a model for the prevention of coronary heart disease. The SUN project ("Se-guimiento Universidad de Navarra") is an epidemiological prospective cohort study of University of Navarre alumni started in 2000 with the main objective of identifying dietary and non-dietary determinants of these disorders. The feasibility of the project was verified in a two-phase pilot study. Method: Volunteers participated in the first phase of the pilot study. Dietary and non-dietary exposures were measured using self-administered questionnaires and interview. A random sample of 600 graduates was selected for the second phase of the pilot study. The selected alumni received a questionnaire by mail. The 10th, 25th, 50th, 75th and 90th percentiles were calculated for the consumption of each food item or nutrient to estimate the inter-subject variability. Results: The participants understood and answered the questionnaires properly. The mean time spent in completing the questionnaire was 55 minutes (95% CI: 50.7-59.3). A wide inter-subject variability was found in the consumption of food items considered as more representative of the Mediterranean diet (olive oil, fruits, vegetables and wine) with major differences between the 10th and 90th percentile. A Mediterranean diet pattern was found with a wide inter-subject variability. Conclusions: The response rate was acceptable. This finding is likely to ensure the identification of associations between the consumption of given food items and the occurrence of the main outcomes we are targeting.
Article
Background: Diet has been reported to influence arterial blood pressure, and evidence indicates that the Mediterranean diet reduces cardiovascular mortality. Objective: The objective was to examine whether the Mediterranean diet, as an entity, and olive oil, in particular, reduce arterial blood pressure. Design: Arterial blood pressure and several sociodemographic, anthropometric, dietary, physical activity, and clinical variables were recorded at enrollment among participants in the Greek arm of the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Of these participants, 20 343 had never received a diagnosis of hypertension and were included in an analysis in which systolic and diastolic blood pressure were regressed on the indicated possible predictors, including a 10-point score that reflects adherence to the Mediterranean diet and, alternatively, the score's individual components and olive oil. Results: The Mediterranean diet score was significantly inversely associated with both systolic and diastolic blood pressure. Intakes of olive oil, vegetables, and fruit were significantly inversely associated with both systolic and diastolic blood pressure, whereas cereals, meat and meat products, and ethanol intake were positively associated with arterial blood pressure. Mutual adjustment between olive oil and vegetables, which are frequently consumed together, indicated that olive oil has the dominant beneficial effect on arterial blood pressure in this population. Conclusions: Adherence to the Mediterranean diet is inversely associated with arterial blood pressure, even though a beneficial component of the Mediterranean diet score—cereal intake—is positively associated with arterial blood pressure. Olive oil intake, per se, is inversely associated with both systolic and diastolic blood pressure.
Article
Background Olive oil is the main source of dietary lipids in most Mediterranean countries where mortality and incidence rates for coronary heart disease (CHD) are the lowest in Europe. Although international comparisons and mechanistic reasons support the hypothesis that a high olive oil intake may prevent CHD, limited data from studies of individuals are available. Methods A hospital-based case-control study was conducted in Pamplona (Spain) recruiting 171 patients (81% males, age <80 years) who suffered their first acute myocardial infarction and 171 age-, gender- and hospital-matched controls (admitted to minor surgery, trauma or urology wards). A validated semi-quantitative food frequency questionnaire (136 items) was used to appraise previous long-term dietary exposures. The same physician conducted the face-to-face interview for each case patient and his/her matched control. Conditional logistic regression modelling was used to take into account potential dietary and non-dietary confounders. Results The exposure to the upper quintile of energy-adjusted olive oil (median intake: 54 g/day) was associated with a statistically significant 82% relative reduction in the risk of a first myocardial infarction (OR = 0.18; 95% CI : 0.06–0.63) after adjustment for dietary and non-dietary confounders. Conclusions Our data suggest that olive oil may reduce the risk of coronary disease. These findings require confirmation in further observational studies and trials.
Article
Purpose: To estimate the prevalence of physical activity during leisure time in adults from the 15 member states of the European Union and the relationship with sociodemographic variables. Methods: A representative sample, with approximately 1000 adults. aged 15 and upward, was selected from each member state to complete a questionnaire on attitudes to physical activity, body weight. and health by a face-to-face interview, summing a total of 15,239 subjects. The amount of leisure-time physical activity was quantified by assigning metabolic equivalents (METs) to each activity. Multiple linear regression models with MET-h wk(-1);ls the dependent variable were fitted. Results: Northern European countries showed higher levels of physical activity than southern ones. The highest prevalence (91.9%) was found in Finland, and the lowest (40.7%) in Portugal. A higher percentage of men practiced any leisure-time physical activity and also showed higher mean of MET-h.wk(-1). In both genders, the multivariate models showed it significant trend to higher leisure time activity in participants with higher educational levels and in nonsmokers. Also. an inverse association between body mass index and leisure-time physical activity was found. Conclusion: The prevalence of any physical activity during? leisure time in the adult European population was similar to the U.S. estimates. Nevertheless. the amount of activity is low, and a wide disparity between countries exists. To our knowledge, this is the: first study determining the prevalence and amount of leisure-time physical activity, which is the first step to define strategies to persuade populations to increase their physical activity.
Article
Correspondencia: Dr. M.Á. Martínez-González. Unidad de Epidemiología y Salud Pública. Facultad de Medicina. Universidad de Navarra. Irunlarrea, 1. 31008 Pamplona. Navarra.
Article
Purpose: The Mediterranean diet has been postulated as a protective factor against different diseases including stroke. Thus, an epidemiological study in a Mediterra- nean country, such as Spain, focused on diet may offer new insights of the potential benefits of this nutritional pattern to prevent the onset of cerebrovascular diseases. Methods: The SUN ("Seguimiento Universidad de Navarra") project is a prospective study among Spanish university alumni, aimed to identify the dietary determinants of stroke, coronary disease and other disorders. Two pilot studies have been developed. The first pilot study was focused on the understanding of the questionnaire. The second study used a random sample to assess the response proportion and the feasibility of using a mailing system for following-up the cohort. The first informative results are expected to be available after the first four years of following-up the cohort (2005). Here, we report the description of the baseline diet of the first participants in the cohort using data from 1587 men and 2260 women. Results: The outcome of our pilot studies ensure the feasibility of a mail-based cohort. In the baseline assessment, we found a high consumption of olive oil (18.5 g/person/day), red wine (28.8 g/person/day), legumes (102.5 g/person/day), vegetables (507.8 g/person/ day) and fruits (316.7 g/person/day), with a great between-subject variability. Also, the values for cereals (170.4 g/person/day), dairy products (239.3 g/person/day) and meat and meat products consumption (186 g/person/ day) in this cohort were estimated. The coefficients of variation ranged in women from 56 (for vegetables) to 240% (for red wine) and in men from 62 to 180% (for these same two items), reflecting a wide heterogeneity in the diet of participants. Conclusions: Although the participation was not high (22% according to the estimates of the pilot study), it was comparable to the proportion found in large previous cohorts such as the Nurses-II Health Study (24%). The sharp contrast in dietary habits between the US and Spain together with the high between-subjects varia- bility we have found in our Spanish cohort provides an exceptional opportunity to assess the aspects of the Mediterranean diet, which may be protective against stroke and other neurological disorders.
Book
This book is intended to increase understanding of the complex relationships between diet and the major diseases of western civilization, such as cancer and atherosclerosis. The book starts with an overview of research strategies in nutritional epidemiology-a relatively new discipline which combines the knowledge compiled by nutritionists during this century with the methodology developed by epidemiologists to study the determinants of disease with multiple etiologies and long latent periods. A major part of the book is devoted to methods of dietary assessment using data on food intake, biochemical indicators of diet, and measures of body size and composition. The reproducibility and validity of each approach and the implications of measurement error are considered in detail. The analysis, presentation, and interpretation of data from epidemiologic studies of diet and disease are discussed. Particular attention is paid to the important influence of total energy intake on findings in such studies. As examples of methodologic issues in nutritional epidemiology, three substantive topics are examined in depth: the relations of diet and coronary heart disease, fat intake and breast cancer, and Vitamin A and lung cancer.
Article
Cardiovascular diseases are the main cause of death worldwide at the turn of the XXI century [1]. Although it has been projected that by 2020, 71% of deaths due to ischaemic heart disease (IHD), will occur in developing countries [2], developed countries currently continue to exhibit unacceptable high absolute rates of cardiovascular mortality. Interestingly, IHD has a surprisingly low incidence in some developed countries such as France, Spain, Greece, Italy or Portugal, leading to a higher life expectancy in Mediterranean areas as compared with Northern European countries or the USA [3]. Diet and lifestylerelated factors may be responsible for this advantage. The role of diet on IHD has been studied during almost a century, and substantial evidence about the protection by some nutrients and food items is cur
Article
To create a suitable instrument to estimate intakes of total calories, protein, carbohydrate, fats (saturated, mono and polyunsaturated), alcohol, cholesterol, fibre, vitamin A and vitamin C in epidemiological studies conducted in Spain, a food frequency questionnaire was developed and tested. In particular, the questionnaire was designed to be used in a large population-based case-control study of dietary factors in relation to breast and colorectal cancer among women from different Spanish regions. After identifying the most important food sources of the relevant nutrients in the study population, the final version of the questionnaire asked about consumption of 118 food items. Its reproducibility and validity were tested among 147 Spanish women aged 18-74 years. These subjects were asked to complete the questionnaire before and after completing four 4-day food records. The records were obtained at 3-month intervals designed to represent daily and seasonal changes (between 1990 and 1991). Using the information available from standard Spanish food composition tables, an ad hoc computer program was created to translate food consumption into nutrient intake. The reproducibility of the questionnaire was assessed by means of estimating correlations between nutrient scores measured with the same instrument twice, with a period of 1 year between estimates. Pearson correlation coefficients ranged from 0.51 for saturated fat to 0.88 for alcohol. In the validity study, correlation coefficients between diet records and the first and second questionnaires ranged between r = 0.20 for vitamin A and r = 0.88 for alcohol.(ABSTRACT TRUNCATED AT 250 WORDS)