Association of secondhand tobacco smoke exposure during childhood on adult cardiovascular disease risk among never-smokers.

PURPOSE: Adult secondhand tobacco smoke (SHS) exposure is related to stroke and coronary heart disease (CHD) risk, but long-term effects are less clear. We evaluated whether childhood SHS exposure affects subsequent stroke or CHD risk among adult black and white never-smokers followed for stroke and CHD. METHODS: In this prospective cohort study, inverse probability weights were calculated to correct for bias due to attrition and survey nonresponse. Cox proportional hazards models were used to assess hazard ratios and 95% confidence intervals for stroke or CHD, separately, by number of childhood household smokers. RESULTS: Of 13,142 eligible participants, 6136 had childhood SHS exposure assessed. Baseline mean (SD) age was 63.5 (9.0), 65% were female, 30% black, 46% reported 0 childhood household smokers, 36% reported 1, and 18% reported 2+. In 60,649 person-years, 174 strokes were observed (2.9% of participants), and in 45,195 person-years, 114 CHD events were observed (2.1% of participants). The weighted and adjusted hazard ratios (95% confidence intervals) of stroke for 2+ versus 0 childhood household smokers was 1.66 (1.29-2.13) and was 1.15 (0.82-1.59) for CHD. CONCLUSIONS: We observed a significant association between childhood SHS exposure and stroke, but not CHD, after age 45 years and adjusting for missing information.

Prevalence of Autism Spectrum Disorders with and without Intellectual Disability by Gestational Age at Birth in the Stockholm Youth Cohort: a Register Linkage Study.

BACKGROUND: Preterm birth has been linked to increased risk of autism spectrum disorders (ASD), but how this risk changes with gestational age at birth has not been well characterised, especially with regard to co-occurring intellectual disability (ID). METHODS: Register-based cohort study of singleton births in 1984-2007 in Stockholm County, Sweden (N total: 480 728; n ASD: 10 025). We assessed overall and sex-specific, gestational week-specific prevalence estimates and risk ratios of ASD with and without ID. RESULTS: Preterm and postterm births were associated with elevated risk of ASD, and the relationship between gestational age at birth and ASD with and without ID differed in males and females. Risk of ASD without ID was higher in preterm births among both sexes and decreased continuously with increasing length of gestation. Risk of ASD with ID was higher in both preterm and postterm births among both sexes, with postterm birth in females being more highly associated with ASD with ID than that in males. CONCLUSIONS: The relationship between gestational age at birth and ASD differs by the presence/absence of co-occurring ID and fetal sex. Both preterm and postterm birth are associated with increased risk of ASD. Risk of ASD is not constant within conventionally defined gestational age at birth periods. Further research on mechanism underlying these associations is needed.