Margaret de Groh

Long-term Association Between Leisure-time Physical Activity and Changes in Happiness: Analysis of the Prospective National Population Health Survey

Happiness is among the most fundamental of all human goals. Although the short-term association between physical activity and happiness is well known, the long-term associations are not. Data from the National Population Health Survey cycles conducted between 1994/1995 and 2008/2009 (cycles 1 through 8) were analyzed. Happy respondents were classified as physically active or inactive at baseline and then were followed up in subsequent cycles to examine their likelihood of becoming unhappy. Individuals who changed their activity level also were examined. After controlling for potential confounding factors, the authors found that leisure-time physical activity (LTPA) was associated with reduced odds of unhappiness after 2 years and 4 years. People who were inactive in 2 consecutive cycles were more than twice as likely to be unhappy as those who remained active in both cycles after 2 years. Compared with those who became active, inactive participants who remained inactive were also more likely to become unhappy. A change in LTPA from active to inactive was associated with increased odds of becoming unhappy 2 years later. This study suggests that LTPA has a long-term association with happiness. Changes in LTPA are associated with subsequent mood status.

Increasing blood pressure and its associated factors in Canadian children and adolescents from the Canadian Health Measures Survey

BackgroundCanada is facing a childhood obesity epidemic. Elevated blood pressure (BP) is a major complication of obesity. Reports on the impact of excess adiposity on BP in children and adolescents have varied significantly across studies. We evaluated the independent effects of obesity, physical activity, family history of hypertension, and socioeconomic status on BP in a nationally representative sample of children and adolescents.MethodsWe analysed cross-sectional data for 1850 children aged 6 to 17 years who participated in the Canadian Health Measures Survey, Cycle 1, 2007–2009. Systolic BP (SBP) and diastolic BP (DBP) were age-, sex-, and height-adjusted to z-scores (SBPZ and DBPZ). Body mass index (BMI) z-scores were calculated based on World Health Organization growth standards. Multivariate linear regression was used to evaluate the independent effects of relevant variables on SBPZ and DBPZ.ResultsFor most age/sex groups, obesity was positively associated with SBP. Being obese was associated with higher DBP in adolescent boys only. The BP effect of obesity showed earlier in young girls than boys. Obese adolescents were estimated to have an average 7.6 mmHg higher SBP than normal weight adolescents. BMI had the strongest effect on BP among obese children and adolescents. Moderately active adolescent boys had higher SBP (3.9 mmHg) and DBP (4.9 mmHg) than physically active boys. Family history of hypertension showed effects on SBP and DBP in younger girls and adolescent boys. Both family income and parent education demonstrated independent associations with BP in young children.ConclusionsOur findings demonstrate the early impact of excess adiposity, insufficient physical activity, family history of hypertension, and socioeconomic inequalities on BP. Early interventions to reduce childhood obesity can, among other things, reduce exposure to prolonged BP elevation and the future risk of cardiovascular disease.

Dietary transfatty acids and cancer risk.

This study assesses the association between dietary transfatty acid (TFA) intake and the risk of selected cancers. Mailed questionnaires were completed between 1994 and 1997 in eight Canadian provinces by 1182 incident, histologically confirmed cases of the stomach, 1727 of the colon, 1447 of the rectum, 628 of the pancreas, 3341 of the lung, 2362 of the breast, 442 of the ovary, 1799 of the prostate, 686 of the testis, 1345 of the kidney, 1029 of the bladder, 1009 of the brain, 1666 non-Hodgkin’s lymphomas, 1069 leukemias, and 5039 population controls. Information on dietary habits and nutrition intake was obtained using a food frequency questionnaire, which provided data on eating habits 2 years before the study. Odds ratios (OR) and 95% confidenc530e intervals (CI) were derived by unconditional logistic regression to adjust for total energy intake and other potential confounding factors. Dietary TFA were positively associated with the risk of cancers of the colon (OR: 1.38 for the highest vs. the lowest quartile), breast in premenopause (OR: 1.60), and prostate (OR: 1.42). There were a borderline association for pancreas cancer (OR: 1.38; P=0.06). No significant association was observed for cancers of the stomach, rectum, lung, ovary, testis, kidney, bladder, brain, non-Hodgkin’s lymphomas, and leukemia, although the ORs for the highest quartile were above unity for all neoplasms considered, except testis. Our findings add evidence that high TFA is associated with an increased risk of various cancers. Thus, a diet low in transfat may play a role in the prevention of several cancers.

Genetic modifiers of folate, vitamin B-12, and homocysteine status in a cross-sectional study of the Canadian population

BACKGROUND Genetic variation can cause variable responses to environmental stimuli. A number of single-nucleotide polymorphisms (SNPs) have been associated with B vitamin status or chronic diseases related to vitamin B-12 and folate metabolism. OBJECTIVE Our objective was to identify associations between common SNPs in genes related to folate and vitamin B-12 metabolism or associated with B vitamin-related chronic diseases and biomarkers of nutrient status in a population exposed to folic acid fortification. DESIGN A panel of 116 SNPs was sequenced by using the Sequenom iPLEX Gold platform in a sample of 3114 adults aged 20-79 y from the Canadian Health Measures Survey, cycle 1. Associations between these SNPs and red blood cell (RBC) folate, serum vitamin B-12, and plasma total homocysteine were determined. RESULTS Twenty-one SNPs and 6 haplotype blocks were associated with RBC folate, serum vitamin B-12, and/or plasma homocysteine concentrations. Vitamin status was associated mainly with SNPs in genes directly involved in vitamin absorption/uptake (CUBN, CD320), transport (TCN1, TCN2), or metabolism (BHMT2, CBS, MTHFR, MUT, SHMT1). Other SNPs included those in the DNMT2, DPEP1, FUT2, NOX4, and PON1 genes. CONCLUSIONS We identified novel associations between SNPs in CD320 and DNMT2, which had been previously associated with neural tube defects, and vitamin B-12 status, as well as between SNPs in SHMT1, which had been previously associated with colorectal cancer and cardiovascular disease risk, and RBC folate status. These novel associations provide a plausible metabolic rationale for the association of these SNPs with B vitamin-related diseases. We also observed a novel association between an SNP in CUBN with RBC folate and confirmed the association of a number of SNPs with B vitamin status in this large cross-sectional study.

Rising incidence of adenocarcinoma of the lung in Canada

BACKGROUND/AIMS This study examines temporal trends in incidence of lung cancer in 1972-2007, temporal trends in histological types of lung cancer in 1988-2007, and age-period-cohort effects on the incidence rates of lung cancer in Canada. METHODS Using incidence data for 1972-2007, we calculated the three-year period rates and annual percentage change (APC): from 1988 to 2007 we were able to do this by histological types. We used age-period-cohort modelling to estimate underlying effects on the observed trends in incidence of adenocarcinoma of the lung. RESULTS In Canada, age-adjusted incidence rates have increased by 263% in women and 4% in men from 1972 to 2007. Annual percent change in age-adjusted rates for women by histological type from 1988 to 2007 were 2.2% for adenocarcinoma, -0.9% for squamous cell carcinoma and -0.4% for small cell carcinoma. Age-adjusted rates decreased for men over the same 20 years: adenocarcinoma (APC: -0.6%), squamous cell carcinoma (APC: -4.2%) and small cell carcinoma (APC: -3.2%) in men. Age-specific incidence rates increased most rapidly for adenocarcinoma in those aged 75+ years (APC: women 4.3%; APC: men 1.1%). The age-period-cohort modelling suggested that the risk of being diagnosed with adenocarcinoma is decreasing in men and will be decreasing slowly in women. CONCLUSIONS The adenocarcinoma incidence trends observed are consistent with smoking trends, however, the relative risk with smoking is lower for adenocarcinoma than for squamous cell carcinoma and small cell carcinoma. This suggests that other exposures may play a role in adenocarcinoma incidence, such as exposure to environmental carcinogens.

Assessment of Dietary Sodium and Potassium in Canadians Using 24-Hour Urinary Collection.

BACKGROUND Although salt intake derived from data on urinary sodium excretion in free-living populations has been used in public policy, a population study on urinary sodium excretion has not been done in Canada. We assessed dietary sodium and potassium intake using a 24-hour urine collection in a large survey of urban and rural communities from 4 Canadian cities and determined the association of these electrolytes with blood pressure (BP). METHODS One thousand seven hundred consecutive individuals, aged 37-72 years, attending their annual follow-up visits of the ongoing Prospective and Urban Rural Epidemiology (PURE) study in Vancouver, Hamilton, Ottawa, and Quebec City, Canada, collected a 24-hour urine sample using standardized procedures. RESULTS Mean sodium excretion was 3325 mg/d and mean potassium excretion was 2935 mg/d. Sodium excretion ranged from 3093 mg/d in Vancouver to 3642 mg/d in Quebec City, after adjusting for covariates. Potassium excretion ranged from 2844 mg/d in Ottawa to 3082 mg/d in Quebec City. Both electrolytes were higher in men than in women and in rural populations than in urban settings (P < 0.001 for all). Sodium excretion was between 3000 and 6000 mg/d in 48.3% of the participants, < 3000 mg/d in 46.7%, and > 6000 mg/d in only 5%. No significant association between sodium or potassium excretion and BP was found. CONCLUSIONS Sodium consumption in these Canadians is within a range comparable to other Western countries, and intake in most individuals is < 6000 mg/d, with only 5% at higher levels. Within this range, sodium or potassium levels were not associated with BP.

Socio-demographic and lifestyle factors associated with folate status among non-supplement-consuming Canadian women of childbearing age

Objective: Mandatory folic acid fortification was implemented in Canada in 1998 to reduce the risk of neural tube defects (NTD). Our objective was to assess the relationship between socio-demographic factors and folate status in non-supplement-consuming Canadian women of childbearing age.METHODS: Data on demographic factors, lifestyle factors, physical measures and red blood cell (RBC) folate concentration were collected from 1,008 non-supplement-consuming women aged 15-49 years in the Canadian Health Measures Survey (2007–2009). RBC folate ≥906 nmol/L was used as a cut-off for optimal folate status for protection from NTD.RESULTS: Approximately 75% of non-supplement consuming women had an RBC folate concentration ≥906 nmol/L. Young age (15-19 years), White ethnicity, less than secondary education, lowest income adequacy, smoking and high body mass index were associated with a higher prevalence of lower folate status. After adjustment, only young age (adjusted odds ratio [OR] 1.99–95% confidence interval [CI]: 1.25–3.18) was associated with lower folate status. Less than secondary education (adjusted OR 5.66, 95% CI: 1.10–29.04) and lowest income adequacy (adjusted OR 4.77, 95% CI: 1.06–21.49) were associated with lower folate status in women aged 15-24 and 25-49 years, respectively.CONCLUSIONS: Many risk factors for lower folate status identified before food fortification was implemented were not associated with folate status in our representative sample of non-supplement-consuming Canadian women. However, younger women, women aged 15-24 with less than secondary education and women aged 25-49 with low income adequacy remain at risk of lower folate status, supporting the continued promotion of folic acid supplement use to women of childbearing age.RésuméOBJECTIF: Appliqué au Canada depuis 1998, l’enrichissement obligatoire en acide folique vise à réduire le risque d’anomalies du tube neural (ATN). Notre objectif était d’évaluer la relation entre les facteurs sociodémographiques et le statut en folates chez les Canadiennes en âge de procréer ne consommant pas de suppléments.MÉTHODE: Des données sur les facteurs démographiques, les facteurs liés au mode de vie, les indicateurs physiques et la concentration en folates érythrocytaires ont été recueillies auprès de 1 008 femmes de 15 à 49 ans ne consommant pas de suppléments et ayant participé à l’Enquête canadienne sur les mesures de la santé (2007–2009). Un seuil de folates érythrocytaires ≥906 nmol/L a servi à délimiter le statut optimal en folates qui protège contre les ATN.RÉSULTATS: Environ 75 % des femmes ne consommant pas de suppléments avaient une concentration en folates érythrocytaires ≥906 nmol/L. La jeunesse (15-19 ans), l’ethnicité blanche, le fait d’avoir moins qu’un diplôme d’études secondaires, la catégorie inférieure de revenu adéquat, le tabagisme et un indice de masse corporelle élevé étaient associés à une prévalence accrue du faible statut en folates. Après correction, seule la jeunesse (rapport de cotes ajusté [RC] 1,99, intervalle de confiance de 95 % [IC]: 1,25–3,18) était associée au faible statut en folates. Le fait d’avoir moins qu’un diplôme d’études secondaires (RC ajusté 5,66, IC de 95 %: 1,10–29,04) et la catégorie inférieure de revenu adéquat (RC ajusté 4,77, IC de 95 %: 1,06–21,49) étaient associés au faible statut en folates chez les femmes de 15 à 24 ans et de 25 à 49 ans, respectivement.CONCLUSIONS: De nombreux facteurs de risque de faible statut en folates, identifiés avant la mise en oeuvre de l’enrichissement des aliments, n’étaient pas associés au statut en folates dans notre échantillon représentatif de Canadiennes ne consommant pas de suppléments. Toutefois, les jeunes femmes, les femmes de 15 à 24 ans n’ayant pas terminé leurs études secondaires et les femmes de 25 à 49 ans dans la catégorie inférieure de revenu adéquat courent encore le risque d’avoir un faible statut en folates, ce qui justifie que l’on continue à promouvoir la supplémentation en acide folique chez les femmes en âge de procréer.

Increasing incidence in liver cancer in Canada, 1972-2006: Age-period-cohort analysis

BACKGROUND/AIMS Our study aimed to assess 1) the temporal trends in incidence and mortality of liver cancer and 2) age-period-cohort effects on the incidence in Canada. METHODS We analyzed data obtained from the Canadian Cancer Registry Database and Canadian Vital Statistics Death Database. We first examined temporal trends by sex, age group, and birth cohort between 1972 and 2006. Three-year period rates and annual percentage change (APC) were calculated to compare the changes over the study period. We used age-period-cohort modelling to estimate underlying effects on the observed trends in incidence. RESULTS The overall age-adjusted incidence rates increased from 2.6 and 1.5 per 100 000 in 1972-74 to 6.5 (APC: 2.9) and 2.2 (APC: 1.2) per 100 000 in 2004-06 among males and females, respectively. The age-adjusted mortality rates increased from 3.3 and 2.0 per 100 000 in 1972-74 to 6.0 (APC: 2.3) and 2.6 (APC: 1.2) per 100 000 in 2004-06 among males and females, respectively. The incidence increased most rapidly in men aged 45-54 years (APC: 4.1) and women aged 65-74 years (APC: 1.7) over the period of study. CONCLUSIONS The age-period-cohort analysis suggests that birth-cohort effect is underlying the increase in incidence. While the exact reason for the increased incidence of liver cancer remains unknown, reported increase in HBV and HCV infections, and immigration from high-risk regions of the world may be important factors.

A Case-Control Study of Risk Factors for Salivary Gland Cancer in Canada

Aim. To assess the effect of various lifestyle risk factors on the risk of salivary gland cancer in Canada using data from a population-based case-control study. Methods. Data from a population-based case-control study of 132 incident cases of salivary gland cancer and 3076 population controls were collected through self-administered questionnaire and analysed using unconditional logistic regression. Results. Four or more servings/week of processed meat product was associated with an adjusted odds ratio (OR) and corresponding 95% confidence interval (CI) of 1.62 (1.02–2.58). Nonsignificantly increased ORs were also related to obesity, >7 drinks/week of alcohol consumption, and occupational exposure to radiation. Furthermore, nonsignificantly decreased ORs were found to be associated with high education level (>12 years) (OR = 0.65), high consumption of spinach/squash (OR = 0.62) and all vegetables/vegetable juices (OR = 0.75), and >30 sessions/month of recreational physical activity (OR = 0.78). Conclusions. This study suggests positive associations with consumption of processed meat, smoking, obesity, alcohol drinking, and occupational exposure to radiation as well as negative associations with higher education, consumption of spinach/squash, and physical activity, which suggest a role of lifestyle factors in the etiology of salivary gland cancer. However, these findings were based on small number of cases and were nonsignificant. Further larger studies are warranted to confirm our findings.