Effects of maternal smoking during pregnancy on offspring blood pressure in late adolescence.

OBJECTIVES: Previous studies suggest that maternal smoking during pregnancy is associated with elevated offspring blood pressure during childhood. We aimed to investigate whether this association remained in late adolescence and, if so, whether it could be attributed to an intrauterine effect or to familial confounding. METHODS: We used a national cohort of 87,223 young Swedish men born between 1983 and 1988 with information on both maternal smoking during pregnancy and blood pressure at military conscription. The cohort included 780 full brothers discordant for maternal smoking. Generalized estimation equations were used to estimate regression coefficients (ß) with 95% confidence intervals (95% CIs). RESULTS: We found a small but significant increase in both SBP and DBP for young men whose mothers had been daily smokers during pregnancy compared with sons of nonsmoking mothers: 0.26 (95% CI 0.09 to 0.44) and 0.45 mmHg (95% CI 0.31 to 0.59) for SBP and DBP, respectively. In a within-sibling analysis comparing full brothers discordant for maternal smoking exposure, point estimates were similar but not statistically significant: 0.85 (95% CI -0.19 to 1.90) for DBP and 0.81 (-0.56 to 2.19) for SBP. CONCLUSION: Maternal smoking during pregnancy is associated with a small but statistically significant increase in offspring blood pressure in late adolescence. Because the association does not appear to be explained by familial confounding, our results support an intrauterine effect of prenatal smoking exposure on blood pressure in late adolescence.

Intergenerational social mobility and the risk of hypertension.

BACKGROUND: Low socioeconomic status (SES) has been linked to increased risk of hypertension, a known risk factor for cardiovascular disease. How the risk is altered by intergenerational social mobility is not well known. The aim of this study is to investigate parental SES, adult SES and the intergenerational social mobility in relation to hypertension risk. METHODS: By using data from the Swedish Twin Registry, the authors obtained information about both parental and adult SES and hypertension in 12 030 individuals born from 1926 to 1958. Generalised estimating equations were used to estimate ORs with 95% CIs. RESULTS: Low parental SES was associated with increased odds of hypertension (OR 1.42, 95% CI 1.14 to 1.76). Low SES in adulthood was associated with increased odds for women but not for men (OR 1.40, 95% CI 1.15 to 1.70 and OR 1.01, 95% CI 0.83 to 1.24, respectively). Compared with the stable low social status group, the upward mobile group had lower odds of hypertension (OR 0.82, 95% CI 0.70 to 0.97). Compared with the stable high social status group, the results for the downward mobile group indicated an increased risk. A co-twin case-control analysis indicated that the results were independent of familial factors. CONCLUSIONS: These findings suggest that the risk of hypertension associated with low parental social status can be modified by social status later in life. Possibly, this could be targeted by public health or political interventions. As parental social status has an impact on later health, such interventions should be introduced early.