Women with gestational diabetes who adhered to a healthy diet had a 20% lower risk for developing high blood pressure later in life, according to data published in Hypertension.
Researchers evaluated 3818 women with a history of gestational diabetes enrolled in the Nurses’ Health Study II as part of the ongoing Diabetes & Women’s Health Study. These women were followed from 1989 to 2011. The researchers identified incident hypertension via self-administered questionnaires that were validated by medical record review.
They also computed adherence scores for the alternative Healthy Eating Index 2010 (HEI), the alternative Mediterranean diet, and the Dietary Approaches to Stop Hypertension (DASH) diet for each participant. Similarities among the diets include eating fruits and vegetables, fish, legumes, and whole grains while reducing red meat, salt, and processed meat.
During a median of 18.5 years of follow-up, 1069 women developed hypertension. After adjustment for smoking, physical activity level, race/ethnicity, oral contraceptive use, family history of hypertension, and weight, the researchers observed significant inverse associations between alternative HEI, alternative Mediterranean diet, and DASH diet scores and hypertension risk. Hazard ratios (HRs) for the highest vs lowest quartiles were 0.76 (95% CI, 0.61-0.94), 0.70 (95% CI, 0.56-0.88), and 0.72 (95% CI, 0.58-0.90), respectively.
The researchers also noted that women with greater adherence to a healthy diet were less likely to be smokers and consume trans fat and were more likely to be moderate alcohol drinkers, eat more cereal fiber, and be physically active.
“Our earlier research showed that diabetes in pregnancy increased a woman’s risk of developing hypertension, even 16 years after giving birth,” Cuilin Zhang, MD, PhD, senior study author and senior investigator at the Eunice Kennedy Shriver National Institute of Child Health and Human Development in Rockville, Maryland, said in a press release. “Our current study shows that a healthy diet, which has been proven to reduce high blood pressure risk in the general population, appears to be equally effective in reducing the risk in this group of high-risk women.”
Results revealed that increase in BMI accounted for about 20% to 30% of the association between lower healthy dietary pattern scores and increased risk for hypertension. BMI change mediated 43.9% of the association for the alternative HEI score (P=.006), 13.8% of the association for the DASH diet score (P=.4), and -10.9% for the alternative Mediterranean diet score (P=.6).
The researchers also plotted the predicted incidence rate of hypertension by the joint effects of diet scores and baseline BMI and the joint effects of diet scores and changes in BMI. Results indicated that probabilities were generally higher for women who gained weight or who were obese throughout the study vs those who lost weight during follow-up.
“While the majority of these women’s glucose levels will return to normal after delivery, our study should serve as an early warning signal,” Dr Zhang said, noting that women with gestational diabetes are usually advised to reduce calories, especially those from carbohydrates, and increase exercise. These results should encourage women to continue these healthy behaviors even after gestational diabetes resolves.
Shanshan Li, MD, MSc, ScD, of the Harvard T.H. Chan School of Public Health and first co-author, noted that participants in the Nurses’ Health Study II are primarily white and educated. Therefore, Dr Li said future studies should evaluate the association between gestational diabetes, diet, and hypertension in minority populations, such as Hispanic and African American women, who have a higher risk for hypertension.