Risk of Early Heart Death for Offspring of Obese Moms

Queen’s Medical Research Institute, United Kingdom, and colleagues reported their findings in an article published online August 13 in BMJ.

Rebecca M. Reynolds, PhD, a professor of metabolic medicine in the Endocrinology Unit, British Heart Foundation/University Centre for Cardiovascular Science at the University of Edinburgh and head researcher stated that, "Our results suggest that the intrauterine environment has a crucial and long lasting effect on risk of premature mortality in offspring."

Data were collected from birth records, from 1950 to the present day. The primary outcome measures were death and hospital admissions for cardiovascular events up to January 1, 2012, in individuals aged 34 to 61 years at the time of follow-up.

The study included 28,540 women whose body mass index (BMI) was measured at their first antenatal visit, and their 37,709 offspring. A total of 21% (n = 5993) of the mothers were overweight, and 4% (n = 1141) were obese.

Among the offspring, 6551 deaths occurred from any cause. The highest causes of death were cardiovascular disease (24% of deaths in men and 13% of deaths in women) and cancer (26% of deaths in men and 42% of deaths in women).

All-cause mortality increased significantly in those born to mothers who were obese (hazard ratio [HR], 1.18; 95% confidence interval [CI], 1.03 – 1.35). In addition, there was a nonsignificant trend for increased risk among offspring whose mothers were overweight (HR, 1.02; 95% CI, 0.95 – 1.09). This pattern was the same in both the entire cohort and in mothers with BMI measurements obtained before 20 weeks of pregnancy.

In an adjusted analysis, the mortality risk increased for both the offspring of overweight (adjusted HR [AHR] ratio, 1.11; 95% CI, 1.03 – 1.19) and obese (AHR, 1.35; 95% CI, 1.17 – 1.55) mothers. The researchers adjusted for gestation, when weight was obtained, mother’s age at delivery, social class, current age of offspring, birth weight, and sex of offspring.

Moreover, overweight (AHR, 1.19; 95% CI, 1.09 – 1.30) and obesity (AHR, 1.40; 95% CI, 1.17 – 1.68) in mothers were significantly associated with premature death from all causes in offspring. Birth weight and all-cause mortality were not related, and there was no interaction between birth weight and maternal obesity with respect to outcomes.

Overall, 7.6% of the offspring had hospital admissions for a cardiovascular event. Maternal overweight was significantly associated with other cerebrovascular disease, peripheral artery disease and other cardiovascular disease in the offspring.

Maternal obesity was also significantly associated with other cardiovascular. Similar patterns were observed when data from the women with BMI recorded in early pregnancy were analyzed separately and when the analyses were conducted after adjustment for current socioeconomic status.

Finally, the researchers found that the odds of death were higher in offspring born to mothers with a low or high BMI compared with mothers with a BMI of 23 kg/m2. The odds of death were lowest among offspring born to women with a BMI of 24 to 28 kg/m2.

BMJ. Published online August 13, 2013