Traffic-related air pollution exposure and incidence of stroke in four cohorts from Stockholm.

We investigated the risk of stroke related to long-term ambient air pollution exposure, in particular the role of various exposure time windows, using four cohorts from Stockholm County, Sweden. In total, 22,587 individuals were recruited from 1992 to 2004 and followed until 2011. Yearly air pollution levels resulting from local road traffic emissions were assessed at participant residences using dispersion models for particulate matter (PM10) and nitrogen oxides (NOX). Cohort-specific hazard ratios were estimated for time-weighted air pollution exposure during different time windows and the incidence of stroke, adjusted for common risk factors, and then meta-analysed. Overall, 868 subjects suffered a non-fatal or fatal stroke during 238,731 person-years of follow-up. An increment of 20 µg/m(3) in estimated annual mean of road-traffic related NOX exposure at recruitment was associated with a hazard ratio of 1.16 (95% CI 0.83-1.61), with evidence of heterogeneity between the cohorts. For PM10, an increment of 10 µg/m(3) corresponded to a hazard ratio of 1.14 (95% CI 0.68-1.90). Time-window analyses did not reveal any clear induction-latency pattern. In conclusion, we found suggestive evidence of an association between long-term exposure to NOX and PM10 from local traffic and stroke at comparatively low levels of air pollution.

Associations between diet and the metabolic syndrome vary with the validity of dietary intake data.

BACKGROUND: Underreporting is a common problem in dietary surveys. Few studies have shown the implication of this when investigating diet-disease relations. OBJECTIVE: We investigated how underreporting affects the associations between dietary factors and the metabolic syndrome. DESIGN: Dietary intake measured with a 7-d food record, fasting insulin concentrations, and other variables of the metabolic syndrome were assessed in a cross-sectional study of 301 healthy men aged 63 y. Biological markers for intakes of protein, sodium, and potassium were measured in 24-h urine samples. Underreporters (URs, n = 88) were identified by Goldberg's equation, which compares energy intake with energy expenditure, both expressed as multiples of the basal metabolic rate. Physical activity level was estimated, and individual cutoffs were calculated. RESULTS: The URs had higher nutrient and food densities in their diet than did the non-URs, which suggested that they followed a healthier diet. The URs had a higher prevalence of the metabolic syndrome than did the non-URs (18% and 9%, respectively; P = 0.029). The biological markers confirmed a low validity of the dietary data in the URs. The correlations between fasting insulin concentrations, a central component of the metabolic syndrome, and the intakes of polyunsaturated fats, n-6 fats, and fat from milk products were stronger in the URs than in the non-URs, which indicates that inaccurate data can introduce spurious associations. CONCLUSION: The association between diet and fasting insulin differed between URs and non-URs in this study of 301 healthy men aged 63 y. If URs are not identified and excluded or treated separately in studies in nutritional epidemiology, spurious diet-disease relations may be reported.

Leisure time, occupational and household physical activity, and risk factors for cardiovascular disease in working men and women: the WOLF study.

AIMS: The aim of the present study was to examine the association of leisure time, occupational and household physical activity, as well as a combination of these (total activity), with four major risk factors for cardiovascular disease. METHODS: Cross-sectional data from the Work, Lipids and Fibrinogen (WOLF) study were used. The study population consisted of 10413 employed persons from two regions in Sweden, 7168 men and 3245 women, aged 19 to 70 years. RESULTS: The adjusted prevalence ratio (PR) of having low high density lipoprotein (HDL) cholesterol levels was 0.54 (95% confidence interval (C.I.) 0.46-0.65) for men and 0.55 (95% C.I. 0.41-0.73) for women who were involved in leisure time physical activity on a regular basis compared with persons with a more sedentary lifestyle. The adjusted PR of having elevated plasma fibrinogen was also significantly lower among those with regular leisure time physical activity. Occupational and household physical activity showed different associations among men and women. Women with high self-perceived household physical activity had an adjusted PR of 1.33 (95% C.I. 1.05-1.68) of having low HDL cholesterol levels. Total activity showed strong beneficial associations with several cardiovascular risk factors. Overweight persons seemed to have relatively more benefit from their physical activity with regard to cardiovascular risk factors than leaner persons. Smokers did not have as strong relative decrease in plasma fibrinogen with increasing activity level as non-smokers. CONCLUSION: Leisure time, as well as total physical activity, was associated inversely with cardiovascular risk factors, particularly HDL cholesterol, in both men and women.