Y Chen

University of Ottawa, Ottawa, Ontario, Canada

Are you Y Chen?

Claim your profile

Publications (42)210.94 Total impact

  • J. Wu, Y. Chen, J. Panek
    Synfacts 01/2010; 2010(08):0914-0914.
  • Y Chen, S Wright, R Westfall
    [Show abstract] [Hide abstract]
    ABSTRACT: To determine age and gender distributions of prevalent diabetes and related risk factors for Northern Canadians. Cross-sectional study. The data used were from 78,549 people aged 40 years or more (including 1148 from Northern Canada) who participated in a national survey in 2005. The study questionnaire covered the information on diabetes and potential risk factors. Multiple classification analysis and a logistic regression model were used for multivariate analysis. In Northern Canada, the prevalence of diabetes tended to increase with age more rapidly in women (P=0.013), while the opposite was true for Southern Canada (P<0.001). Compared with women aged 40-54 years, the adjusted odds ratio for diabetes was 3.31 [95% confidence interval (CI) 1.06-10.4] for women aged 55-69 years and 6.39 (95%CI 1.42-22.8) for women aged 70+ years living in Northern Canada. The corresponding odds ratios for men living in Northern Canada were 1.58 (95%CI 0.53-4.71) and 4.30 (95%CI 0.81-22.9), respectively. The prevalence of obesity was higher for women (28.2%) than men (22.5%) in Northern Canada (P=0.041). The gender and age distribution of diabetes is unusual in Northern Canada, where the prevalence increases with age more rapidly in women than in men. Further study is required in order to gain an understanding of the possible genetic, cultural and other reasons for this pattern.
    Public health 12/2009; 123(12):782-6. · 1.26 Impact Factor
  • Y Chen, Q Li, H Johansen
    [Show abstract] [Hide abstract]
    ABSTRACT: To determine sex and age variations in hospital readmissions for chronic obstructive pulmonary disease (COPD) associated with overall and cardiac comorbid conditions. A one-year follow-up study was conducted for 108 726 COPD in-patients aged >or=40 years who were discharged alive after their first admission in the 1999-2000 fiscal year. Within a year, 38 955 of the patients were readmitted to hospital for COPD. The incidence rate of COPD readmission was 49.1% per year. It was higher for men than women aged >or=70 years, but was almost the same for patients aged <70 years. The length of hospital stay and the Charlson Index at baseline moderately predicted 1-year COPD readmission in younger age groups and in female patients. Congestive heart failure at baseline was associated with a 20% increase in incidence that was age-related. Pulmonary heart disease was less common but was a significant predictor in almost all age and sex groups. Ischemic heart disease and arrhythmia were moderate predictors, and were only significant in women. Women aged <70 years had rates of COPD readmission similar to those of men. Cardiac events were strongly associated with COPD readmissions, which were modified by sex and age.
    The International Journal of Tuberculosis and Lung Disease 03/2009; 13(3):394-9. · 2.76 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To determine the changes in the prevalence of obesity in a rural community between 1977 and 2003. A multiple cross-sectional study. The analysis was based on data from four cross-sectional surveys of adults aged 25-59 years, conducted in the town of Humboldt, Saskatchewan in 1977, 1983, 1993 and 2003. People with a body mass index (BMI) > or =30 kg/m(2) were considered to be obese. Average body weight increased by 8 kg for both men and women during the study period. The increase in BMI was greater in adults aged 25-39 years compared with older age groups. The prevalence of obesity increased from 24% in 1977 to 38% in 2003 for men, and from 16% to 32% for women. The change was more pronounced from 1993 to 2003 than from 1977 to 1993, especially among younger adults. Standardized to the 2003 study population by sex, age and smoking status, the prevalence of obesity was 16.8% in 1977, 22.7% in 1983, 24.7% in 1993 and 34.5% in 2003, and was much higher than the Canadian national average (16% in 2003). There was a dramatic increase in the prevalence of obesity in rural adults, and this was greater in younger adults. Changes in cigarette smoking did not explain the increase. There is an urgent need to identify and implement effective interventions to slow if not reverse the trend, particularly in rural populations.
    Public health 12/2008; 123(1):15-9. · 1.26 Impact Factor
  • Y Chen, J Wu, Q Yi, G Huang, T Wong
    [Show abstract] [Hide abstract]
    ABSTRACT: This study was conducted to determine the association between sexually transmitted infection (STI) and the prevalence of depression among the general Canadian population. The analysis was based on data from the Canadian Community Health Survey conducted in 2003 and included 21,560 participants aged 15-49 years. A logistic regression model was used to examine the association between depression and STI history after taking confounding factors (gender, age, marital status, household size, income, education, immigrant status, alcohol use, smoking status and number of chronic diseases) and effect modifiers into consideration. Of the study subjects, 5.3% reported having a history of STI and 7.9% had depression. STI history was significantly associated with depression, with an odds ratio of 1.5 (95% CI 1.1 to 2.2) for men and 1.8 (95% CI 1.4 to 2.3) for women. The association was significant in men younger than 35 years but was not significant in older men. The association tended to be stronger in men who had a high level of income. The association between STI and depression was relatively consistent among female subpopulations. There is a significant association of depression with STI. Health professionals should be aware that groups of STI patients are more likely to have depression and deal with it accordingly.
    Sexually transmitted infections 07/2008; 84(7):535-40. · 2.18 Impact Factor
  • Source
    Y Chen, Y Jiang, Y Mao
    [Show abstract] [Hide abstract]
    ABSTRACT: To examine the associations between excess weight and health-care utilization in general Canadian population. A national survey with a multistage stratified sampling design. A total of 113 603 adults 20 years of age or more in 2003. Self-reported overnight stay as an in-patient during the past 12 months, length of stay, height and weight. The 12-month cumulative incidence of being an in-patient was 6.6% for men and 10.4% for women, with the length of stay in median of 3 nights for the patients. The adjusted odds ratio for obesity associated with being an in-patient was 1.24 (95% confidence interval: 1.109, 1.40) for men and 1.25 (1.14, 1.37) for women. The association between obesity and being an in-patient was significant or marginally significant in all categories of length of stay with an exception of the '1 night' category for men. Underweight men and women had an increased risk of approximately 30%. Underweight was only significantly associated with being an in-patient with a stay of '>7 nights' in both sexes, and only small proportion of participants were underweight. Obesity contributed slightly more than 4% of being an in-patient in the Canadian adults. The population attributable fraction was very small for underweight because of low proportion of cases in that category. Obesity burdens the universal health-care system in Canada.
    International Journal of Obesity 07/2007; 31(6):962-7. · 5.22 Impact Factor
  • Source
    M Lin, Y Chen, R J Sigal
    [Show abstract] [Hide abstract]
    ABSTRACT: Coexisting hypertension increases the morbidity and mortality associated with diabetes, and may be more so in less educated people. We analysed data from 49 904 Canadians 40-64 years of age who participated in the Canadian Community Health Survey, 2000-2001. Multiple classification analysis was used to adjust for covariates. Population weight and design effect of the survey were taken into account in the analysis. The association between hypertension and hospitalization varied according to diabetes and education. The adjusted difference in hospitalization incidence attributable to hypertension was significantly higher for the lower education group than the higher education group, and such a pattern tended to be more pronounced among diabetic people. The adjusted incidence difference attributable to hypertension was higher in the diabetic group (8.8, 95% confidence interval (CI): 4.6, 13.0%) than in the non-diabetic group (4.6, 95% CI: 3.6, 5.6%) for people with low education, but was similar for those with well-educated people. Possible reasons for the modifying effect of education on the relationship among hypertension, diabetes and hospitalization were discussed.
    Journal of Human Hypertension 04/2007; 21(3):225-30. · 2.82 Impact Factor
  • Source
    W Zhao, Y Chen, M Lin, R J Sigal
    [Show abstract] [Hide abstract]
    ABSTRACT: To examine the association between diabetes and the prevalence of depression in different sex and age groups by analysing the cross-sectional data from the National Population Health Survey, conducted in Canada in 1996-1997. A total of 53072 people aged 20-64 years were included in the analysis. Depression was defined as depression scale 5, based on the Composite International Diagnostic Interview Short-Form (CIDI-SF). Respondents who answered the following question affirmatively were considered to have diabetes: 'do you have diabetes diagnosed by a health professional?'. A multiple logistic regression model was used to adjust for potential confounding effects, and a bootstrap procedure was used to take sampling weights and design effects into account. The prevalence of diabetes was much higher in people aged 40-64 years than in people aged 20-39 years (men: 4.7% vs. 0.5%; women: 3.5% vs. 0.8%, respectively). In contrast, people aged 20-39 years had a slightly higher prevalence of depression than those aged 40-64 years (men: 3.1% vs. 2.9%; women: 6.6% vs. 5.4%, respectively). Diabetes was significantly associated with depression in women aged 20-39 years (odds ratio [OR]=2.52, 95% confidence interval [CI]=1.19, 5.32), but not in women aged 40-64 years (OR=1.62, and 95% CI=0.65, 4.06). The association was not significant in both age groups in men, but it tended to be stronger in the younger age group. The data suggest that diabetes is significantly associated with depression, particularly in young adults.
    Public Health 09/2006; 120(8):696-704. · 1.35 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To assess the risk of neonatal mortality and morbidity in vertex-vertex second twins according to mode of delivery and birth weight. Data from a historical cohort study based on a twin registry in the US (1995-1997) were used. Multivariate logistic regression was used to control for maternal age, race, marital status, cigarette smoking during pregnancy, parity, medical complications, gestational age, and other confounders. A total of 86 041 vertex-vertex second twins were classified into two groups: second twins delivered by cesarean section after cesarean delivery of first twin (C-C) (43.0%), second twins whose co-twins delivered vaginally (V-X) (57.0%). In infants of birth weight>or=2500 g group, the risks of noncongenital anomaly-related death (adjusted odds ratio (aOR): 4.64, 95% confidence interval (95% CI): 1.90, 13.92), low Apgar score (aOR: 2.39, 95% CI: 1.43, 4.14), and ventilation use (aOR: 1.31, 95% CI: 1.18, 1.47) were higher in the V-X group compared with the C-C group. No asphyxia-related neonatal deaths occurred in C-C group, whereas the incidence of this death was 0.04% in the V-X group. The risks of neonatal mortality and morbidity are increased in vertex-vertex second twins with birth weight>or=2500 g whose co-twins delivered vaginally compared with second twins delivered by cesarean section after cesarean delivery of first twin.
    Journal of Perinatology 01/2006; 26(1):3-10. · 2.25 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We examined the gender-related association between household exposure to environmental tobacco smoke (ETS) and pulmonary function among 862 children and adolescents aged 6 to 17 years living in the town of Humboldt, Saskatchewan, in 1993. Pulmonary function tests included forced vital capacity (FVC), forced expiratory volume in one second (FEV1), maximum mid-expiratory flow rate (FEF25-75), and flow rates at 75%, 50%, and 25% of vital capacity (Vmax75, Vmax50, and Vmax25). Each pulmonary function test variable was regressed on age, height, weight, and their quadratic and cubic polynomials, with the terms significant at the alpha level of 0.10 being retained. Residuals for the pulmonary function test variables, which are the differences between the observed and predicted values, were calculated. Estimations of ETS exposure were parental smoking status, number of household smokers, total daily cigarette consumption, and number of cigarettes smoked daily at home by household members. Maternal smoking status was significantly related to residual FEF25-75, Vmax75, Vmax50, and Vmax25. Number of household smokers and daily cigarette consumption by household members were significantly associated with FEV1, FEF25-75, Vmax75, Vmax50, and Vmax25, and the association between ETS exposure and pulmonary function was stronger in girls than in boys. Interaction of gender and number of cigarettes smoked daily at home was significantly related to FEF25-75, Vmax75, Vmax50, and Vmax25 among the non-smoking subjects. We concluded that ETS exposure had a larger effect on pulmonary function in girls than in boys.
    Journal of agricultural safety and health 06/2005; 11(2):167-73.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Assess associations between short-term exposure to gaseous pollutants and asthma hospitalisation among boys and girls 6 to12 years of age. A bi-directional case-crossover analysis was used. Conditional logistic regression models were fitted to the data for boys and girls separately. Exposures averaged over periods ranging from one to seven days were used to assess the effects of gaseous pollutants on asthma hospitalisation. Estimated relative risks for asthma hospitalisation were calculated for an incremental exposure corresponding to the interquartile range in pollutant levels, adjusted for daily weather conditions and concomitant exposure to particulate matter. Toronto, Ontario, Canada. A total of 7319 asthma hospitalisations for children 6 to 12 years of age (4629 for boys and 2690 for girls) in Toronto between 1981 and 1993. A significant acute effect of carbon monoxide on asthma hospitalisation was found in boys, and sulphur dioxide showed significant effects of prolonged exposure in girls. Nitrogen dioxide was positively associated with asthma admissions in both sexes. The lag time for certain gaseous pollutant effects seemed to be shorter in boys (around two to three days for carbon monoxide and nitrogen dioxide), as compared with girls (about six to seven days for sulphur dioxide and nitrogen dioxide). The effects of gaseous pollutants on asthma hospitalisation remained after adjustment of particulate matter. The data showed no association between ozone and asthma hospitalisation in children. The study showed positive relations between gaseous pollutants (carbon monoxide, sulphur dioxide, and nitrogen dioxide) at comparatively low levels and asthma hospitalisation in children, using bi-directional case-crossover analyses. Though, the effects of certain specific gaseous pollutants were found to vary in boys and girls.
    Journal of Epidemiology &amp Community Health 02/2003; 57(1):50-5. · 3.39 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The authors examined the interactive effect of smoking and pets at home on the incidence of asthma and the difference between sexes. The longitudinal data from the first two cycles of the National Population Health Survey, conducted in Canada, were used. A total of 12,636 subjects who reported no asthma at baseline were included in the analysis. The 2-yr cumulative incidence of asthma was higher in females than in males. Female sex and household pets demonstrated a significant interaction in the development of asthma. After adjustment for age, immigration and history of allergy, the odds ratio for smoking in relation to the asthma incidence was 2.50 (95% confidence interval: 1.24-5.05) for females who had pets at home and close to unity for those who had no pets. The incidence of asthma was not associated with smoking status and household pets in males. These results indicate that smoking, having pets at home and other environmental factors can partly explain asthma morbidity among female Canadians.
    European Respiratory Journal 12/2002; 20(5):1162-6. · 6.36 Impact Factor
  • Source
    R E Dales, B Choi, Y Chen, M Tang
    [Show abstract] [Hide abstract]
    ABSTRACT: A study was undertaken to investigate the mechanisms by which socioeconomic status may influence asthma morbidity in Canada. A total of 2968 schoolchildren aged 5-19 years with reported asthma were divided into three family income ranges. Hospital visits and risk factors for asthma, ascertained by questionnaire, were compared between the three groups. The mean (SE) annual period prevalence of a hospital visit was 25.0 (3.1)% among schoolchildren with household incomes of less than $20 000 Canadian compared with 16.0 (1.3)% among those with incomes of more than $60 000 (p<0.05). Students with asthma from lower income households were more likely to be younger and exposed to environmental tobacco smoke and cats, and their parents were more likely to have a lower educational attainment and be unmarried (p<0.05). Across all income groups, younger age, lower parental education, having unmarried parents, and regular exposure to environmental tobacco smoke were each associated with an increase in risk of a hospital visit (p<0.05). No increased risk was detected due to sex, having pets, and not taking dust control measures. Although not statistically significant at p<0.05, there may have been an interactive effect between income and susceptibility to environmental tobacco smoke. In the lower income group those children who were regularly exposed to second hand smoke had a 79% higher risk of a hospital visit compared with a 45% higher risk in the higher income group. In a logistic regression model the association between income and hospital visit was no longer significant after adjusting for differences in reported exposure to passive smoking. Socially disadvantaged Canadian schoolchildren have increased asthma morbidity. Exposure to cigarette smoke appears to be one important explanation for this observation.
    Thorax 07/2002; 57(6):513-7. · 8.38 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We performed segregation analyses of asthma and respiratory allergy based on data from 309 nuclear families comprising 1,053 individuals living in the town of Humboldt, Saskatchewan, in 1993, using the REGD program of the S.A.G.E. program package. For adults, information on asthma and history of respiratory allergy was provided by the subjects themselves, and for children by their parents. When asthma was considered as the trait in segregation analysis, models of no major effect, with or without familial effects, were rejected, but they were not rejected after adjusting for history of respiratory allergy. The major gene hypothesis was not rejected before adjusting for history of respiratory allergy. When respiratory allergy was analyzed as the trait, both major gene and multifactorial models fitted the data well, regardless of whether there was adjustment for asthma or not. Other covariates adjusted for in the segregation analyses were age, sex, number of household smokers, current smoking, number of household members, generation, and house type. The data suggest that a major gene related to respiratory allergy may explain the familial aggregation of asthma.
    American Journal of Medical Genetics 12/2001; 104(1):23-30.
  • Y Chen, R Dales, D Krewski
    [Show abstract] [Hide abstract]
    ABSTRACT: Asthma is an important determinant of hospitalization. The study aims to examine the modifying effects of demographic and socioeconomic factors on the relationship between asthma and the overall number of hospitalizations. We examined the data on 17,601 Canadians who were > or = 12 years of age to explore the combined effects of asthma and other factors on hospitalization within the context of a publicly funded health-care system. Asthma was determined by an affirmative response to the question: "Do you have asthma diagnosed by a health professional?" The subjects also were asked whether they had been an overnight patient in a hospital during the past 12 months. Asthma as a risk factor explained 3.7% of all hospitalizations of men and 2.4% of all hospitalizations of women. Overall, hospitalization was positively associated with female gender, old age, and low household income. The odds ratio for asthma as a risk factor for overall hospitalization (ie, hospitalization for any reason and all causes, not only for asthma) was greater for younger men than for older men, for less-educated women than for well-educated women, and for men with middle or high incomes than for men with low incomes. These results suggest that demographic and socioeconomic factors play a role in the relationship between asthma and the overall number of hospitalizations, with certain population subgroups being at greater risk of hospitalization in relation to asthma.
    Chest 04/2001; 119(3):708-13. · 5.85 Impact Factor
  • Source
    Y Chen, R Dales, D Krewski
    [Show abstract] [Hide abstract]
    ABSTRACT: An association between obesity and asthma has been documented previously, but the nature of this relationship remains unknown. This study aimed to determine if asthma is associated with a sedentary lifestyle which may explain this association. The energy expenditure (EE) on leisure activities was examined in 16,813 subjects, of at least 12 years of age, who participated in the Canadian National Population Health Survey 1994-95. Energy expenditure was calculated by multiplying the duration of leisure-time physical activity by its estimated metabolic energy cost. Asthma was considered to be present if an affirmative response was given to the question, 'Do you have asthma diagnosed by a health professional?' The average EE (+/- standard error) in males was 2.47 (+/- 0.11) kcal kg(-1) day(-1) for asthmatics and 1.98 (+/- 0.03) kcal kg(-1) day(-1) for non-asthmatics. The corresponding average EEs in females were 1.77 (+/- 0.08) and 1.54 (+/- 0.02) kcal kg(-1) day(-1) for asthmatics and non-asthmatics, respectively. The mean EE values decreased with increasing age. A significant interaction between asthma and age was noted with respect to EE; asthmatics tended to have higher mean EE values than non-asthmatics among younger subjects, and lower mean EE values in older subjects. This effect was more pronounced in females than in males. It was concluded that asthmatics were not consistently inactive compared with non-asthmatics. Leisure-time physical activity cannot explain the positive association between obesity and asthma.
    Respiratory Medicine 02/2001; 95(1):13-8. · 2.59 Impact Factor
  • JAMA The Journal of the American Medical Association 01/2001; 286(8):919-20. · 29.98 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The etiology of chronic obstructive pulmonary disease (COPD) has not been fully understood. This analysis assessed the prevalence of COPD and its risk factors among Canadian men and women. The analysis was based on the data from 7210 subjects aged 35 to 64 years who participated in the first cycle of National Population Health Survey in 1994-1995. COPD was considered present if an affirmative response was given to the question: "Do you have chronic bronchitis or emphysema diagnosed by a health professional?" In order to take the complex survey design into account, analytic weights incorporating a design effect were used in all statistical analyses. The prevalence of COPD was 2.1% in nonsmokers, 2.7% in ex-smokers, and 8.2% in smokers in women. In men, the corresponding prevalence was 0.8%, 2.9%, and 3.5%, respectively. The adjusted odds ratio for current smoking men and women who started smoking before age of 18 years was 3.0 and 5.9 compared with their nonsmoking counterparts. Overweight women demonstrated a 2.4-fold increase in the prevalence of COPD compared with women with normal weight. Men from low-income families had an odds ratio of 3.7 compared with those from high-income families. A history of allergy was significantly related to COPD in both men and women. COPD was common among Canadian women. Early initiation of smoking and being overweight had stronger relationships to the prevalence of COPD in women than in men. On the contrary, household income was more strongly related to COPD for men than for women.
    Journal of Clinical Epidemiology 08/2000; 53(7):755-61. · 5.33 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Two to 11% of women diagnosed with breast cancer will develop contralateral breast cancer in their lifetime. Women with a first primary are at a 2-6-fold increased risk of developing contralateral breast cancer compared with the risk in the general population of women developing a first primary cancer. The incidence rate of contralateral breast cancer varies from four to eight per 1000 person-years. To assess the risk factors associated with the development of contralateral breast cancer among women with a first primary breast cancer, the epidemiological literature concerning these factors was reviewed and summarized. Studies have shown that a family history of breast cancer, an early age at initial diagnosis, and a lobular histology of the first primary breast cancer increase the risk of developing contralateral breast cancer. Although chemotherapy and tamoxifen therapy may reduce this risk, there are inconsistent results regarding the effects of radiotherapy and the effects of reproductive, environmental and other factors. Additional analytical studies addressing all potential risk factors associated with the development of contralateral breast cancer are necessary in view of the increasing incidence and survival of women with a first primary.
    Cancer Epidemiology Biomarkers &amp Prevention 11/1999; 8(10):855-61. · 4.56 Impact Factor
  • Source
    Y Chen
    Thorax 10/1999; 54(9):818-24. · 8.38 Impact Factor

Publication Stats

1k Citations
210.94 Total Impact Points

Institutions

  • 1998–2009
    • University of Ottawa
      • • Department of Epidemiology and Community Medicine
      • • Faculty of Medicine
      Ottawa, Ontario, Canada
  • 1991–1996
    • University of Saskatchewan
      • Department of Medicine
      Saskatoon, Saskatchewan, Canada