Chronic Diseases in Canada

Volume 26, No. 2-3, 2005

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Titles of Feature Articles

1. Mediterranean dietary components and body mass index in adults: The Peel Nutrition and Heart Health Survey - View Abstract
   Mamdouh M Shubair, R Stephen McColl and Rhona M Hanning

2. Screening mammography participation and invitational strategy: The Quebec Breast Cancer Screening Program, 1998 - 2000 - View Abstract
   Sonia Jean, Diane Major, Louise Rochette and Jacques Brisson

3. An observational study of sun and heat protection during Canada Day outdoor celebrations, 2003 - View Abstract
   ST David, U Chandran, D Paquette, D Scholten, J Wilson, E Galanis, M Becker,
   F Crane, R Lester, T Mersereau, E Wong and D Carr

4. Validity of a 12-item version of the CES-D used in the National Longitudinal Study of Children and Youth - View Abstract
   Christiane Poulin, Denise Hand and Brock Boudreau

5. An analysis of the effect of selection bias on the association of hormone replacement therapy and breast cancer risk - View Abstract
   Ilona Csizmadi, Christine M Friedenreich, Heather E Bryant and Kerry S Courneya

6. A comparison of measures of socioeconomic status for adolescents in a Canadian national health survey - View Abstract
   Beth K Potter, Kathy N Speechley, Iris A Gutmanis, M Karen Campbell, John J Koval and Douglas Manuel

Chronic Diseases in Canada (CDIC) is a quarterly scientific journal focusing on current evidence relevant to the control and prevention of chronic (i.e., non-communicable) diseases and injuries in Canada. Since 1980 the journal has published a unique blend of peer-reviewed feature articles, by authors from the public and private sectors, which may include research from such fields as epidemiology, public/community health, biostatistics, the behavioural sciences and health services. Authors retain responsibility for the content of their papers and opinions expressed are not necessarily those of the CDIC editorial committe, neither of Health Canada nor of the Public Health Agency of Canada.

Abstracts from Feature Articles in Chronic Diseases in Canada Volume 26, No 1, 2005

Article 1: Mediterranean dietary components and body mass index in adults: The Peel Nutrition and Heart Health Survey

Authors: Mamdouh M Shubair, R Stephen McColl and Rhona M Hanning

Abstract:
Diet is a lifestyle factor that contributes to the risk of overweight/obesity and cardiovascular disease. The objective of this study was to examine the hypothesis that a Mediterranean-type dietary pattern (M) is associated with healthy body weights in a large suburban municipality in Ontario. A random cross-sectional sample of 759 adults, 18 to 65 years of age, participated in a telephone survey, which included questions on the frequency of consumption of 60 food categories. Principal components analysis showed that food categories aggregated into six low-order dietary factors and two high-order dietary patterns. The M pattern reflected higher consumption of fruits and vegetables, olive oil and garlic, and fish and shellfish. The non-M pattern reflected high fat/nutrient poor, meats and poultry, and foods high in added sugars. The M-score was inversely related to body mass index (BMI) (p = 0.027). After adjustment for gender, education, income and marital status, a higher M-score predicted a lower BMI in the 40 to 49 year age group. Heart health promotion strategies aimed at preventing adult obesity should emphasize components of a Mediterranean-type diet pattern.

Article 2: Screening mammography participation and invitational strategy: The Quebec Breast Cancer Screening Program, 1998 - 2000

Authors: Sonia Jean, Diane Major, Louise Rochette and Jacques Brisson

Abstract:
In the Quebec Breast Cancer Screening Program, a personalized letter signed by a regional program physician is sent to every woman in the province 50 to 69 years of age, inviting her to have a screening mammogram. A reminder letter is also frequently sent. The aim of this study was to evaluate the influence of this screening invitational strategy on rates of participation. The population studied was comprised of 684,028 women in Quebec aged 50-69. The baseline (expected) monthly mammography screening rate was estimated from the rate of screening mammograms recorded between the date a woman became eligible for screening and the mailing date of her personalized invitational letter; the observed monthly mammography screening rate was calculated after the mailing of the letter. Compared to baseline (expected) screening rates, observed rates were substantially increased (p < .05). The ratios of observed to expected rates were respectively 3.05 and 2.23 in the second and fourth months, respectively, after the letter mailing, coinciding with the mailing of the initial and reminder letters. In the twelve months after the mailing, the ratio of observed to expected rates was 1.68 (95% CI: 1.67-1.69). Twelve months following the mailing, 30 percent of the women who were letter recipients had undergone a screening mammography, compared to an expected cumulative probability of 20 percent for women not receiving a letter. The strength of this effect was similar to one seen in randomised controlled trials.

Article 3: An observational study of sun and heat protection during Canada Day outdoor celebrations, 2003

Authors: ST David, U Chandran, D Paquette, D Scholten, J Wilson, E Galanis, M Becker, F Crane, R Lester, T Mersereau, E Wong and D Carr

Abstract:
The purposes of this study were: (1) to estimate the proportion of people in attendance at the 2003 Canada Day celebrations in the National Capital Region who used sun and heat protective items; (2) to identify factors associated with the utilization of these protective items; and (3) to provide research data to public outdoor event organizers when developing evidence-based plans for safer events. A naturalistic observational cross-sectional method was used to gather information at the 2003 Canada Day celebrations in the National Capital Region on attendees’ demographics, the sun and heat protective items they used and the protective resources available at the event sites. Of the 398 observed attendees, the proportion using any one of the protective items ranged from 3 percent (an open umbrella) to 51.5 percent (sunglasses). Females were more likely to use protective items more than males, and adults more likely than children. Planners of public outdoor events should consider the factors that influence the utilization of sun and heat protective behaviours and the environmental modifications that would allow participants to make safe choices.

Article 4: Validity of a 12-item version of the CES-D used in the National Longitudinal Study of Children and Youth

Authors: Christiane Poulin, Denise Hand and Brock Boudreau

Abstract:
This validation study assessed the degree of confidence that can be placed on inferences from depressive symptoms among adolescents, based on a 12-item version of the Centre for Epidemiological Studies Depression scale (CES-D). This short version of the scale had been developed for application in the National Longitudinal Study of Children and Youth and we refer to it as the CES-D-12-NLSCY. The major data source for the present validation study was a 2002/2003 survey of 12,990 students in junior and senior high school in the Atlantic provinces of Canada. Receiver operating characteristic curve analyses for two different proxy gold standards yielded adequate areas under the curve (AUCs) of .84 and .80, allowing us to establish cut points for three categories of depressive symptoms in the general adolescent population: Minimal (CES-D-12-NLSCY total score 0 to 11), Somewhat Elevated (total score 12 to 20) and Very Elevated (total score 21 to 36). The CES-D-12-NLSCY was found to have acceptable internal consistency (Cronbach=s alpha .85). All but one of the 12 items of the CES-D-12-NLSCY were found to have acceptable discrimination ability. The prevalence of Minimal, Somewhat and Very Elevated depressive symptoms in the adolescent student population of the Atlantic provinces was estimated to be 72.3, 19.5 and 5.5 percent, respectively. A further 2.6 percent of students who responded to fewer than 11 items of the scale were classified as Indeterminate with regards to depressive symptom category. The major threat to the accuracy of the CES-D-12-NLSCY is its lack of inquiry about irritability, which is a key symptom of depression in youth.

Article 5: An analysis of the effect of selection bias on the association of hormone replacement therapy and breast cancer risk

Authors: Ilona Csizmadi, Christine M Friedenreich, Heather E Bryant and Kerry S Courneya

Abstract:
A sensitivity analysis was conducted to determine the impact on measures of effect of a suspected differential participation response rate between hormone replacement therapy (HRT) users and nonusers, among controls recruited to a population-based case-control study of breast cancer. The age-specific prevalence of current HRT use among controls was compared to data from the 1996 Canadian National Population Health Survey (NPHS). Control women identified as current HRT users were randomly re-sampled to replicate the prevalence of HRT use reported by the NPHS. Unconditional logistic regression was conducted to estimate odds ratios (OR) and 95 percent confidence intervals (CI) for the use of HRT and breast cancer risk before and after re-sampling. Multivariate adjusted ORs for breast cancer and estrogen-only and estrogen-progestin formulations were 0.76 (0.53-1.10) and 0.94 (95% CI: 0.64 – 1.38), respectively, using the original case-control controls and 0.99 (0.77-1.27) and 1.57 (95% CI: 1.02 – 2.40), respectively, following re-sampling of the controls. This sensitivity analysis illustrates the extent to which differential participation rates between HRT users and nonusers may affect estimates of measures of effect.

Article 6: A comparison of measures of socioeconomic status for adolescents in a Canadian national health survey

Authors: Beth K Potter, Kathy N Speechley, Iris A Gutmanis, M Karen Campbell, John J Koval and Douglas Manuel

Abstract:
The purpose of this study was to explore and compare measures of socioeconomic status (SES) in a national sample of Canadian adolescents. Issues of missing data and interrelationships among the measures were addressed. Measures of SES included household income, parental education, two parental occupation-based measures, and four neighbourhood proxy indicators. The proportion of adolescents with missing data was largest for household income (21.1 percent). Data were not missing at random, as adolescents missing household income information were less likely to reside in a high income neighbourhood. Pair-wise Spearman correlations ranged from: 0.40-0.79 between neighbourhood SES measures; 0.12-0.37 between household/parental and neighbourhood indicators; and 0.36-0.87 between household/parental measures. Correlations were lower among rural adolescents, particularly for the neighbourhood SES measures. The results highlight both measurement and conceptual challenges for researchers who wish to gain insight into SES-health relationships for adolescents. In particular, the findings emphasize the importance of incorporating multiple measures of SES and suggest a need to further explore the meaning of socioeconomic position for this population.