Lifestyle in Progression from Hypertensive Disorders of Pregnancy to Chronic Hypertension in Nurses' Health Study II : Observational Cohort Study

Hypertensive disorders of pregnancy (HDPs: preeclampsia and gestational hypertension) are associated with earlier onset of chronic hypertension and a higher risk of ischemic heart disease and stroke and affect between 5% and 10% of parous women. There is little guidance for the prevention of chronic hypertension among women with a history of HDPs, and the role of lifestyle in the progression from HDPs to chronic hypertension is unclear, including whether established lifestyle interventions are as effective in women with a history of HDPs as in the general population. The authors undertook the present observational cohort study to investigate the association of four established lifestyle risk factors for high blood pressure (body mass index [BMI], physical activity, adherence to the Dietary Approaches to Stop Hypertension [DASH] diet, and dietary sodium/potassium intake) with the development of chronic hypertension by history of HDPs. Then, the authors examined the extent to which each lifestyle factor modified the progression from HDPs to chronic hypertension. The study cohort was composed of 54,588 parous women aged 32 to 59 years with complete reproductive history and no previous chronic hypertension, stroke, or myocardial infarction, from the Nurses' Health Study II, which sent questionnaires to recruits every other year. In the present study, history of HDPs was defined as occurring after the first of any pregnancy lasting at least 20 weeks that the nurse participants self-reported to have been complicated by a diagnosis of gestational hypertension or pre-eclampsia. At the start of the Nurses' Health Study II in 1989, women retrospectively recalled their weight at age 18 years and reported their current weight and subsequently recorded their current weight at each biennial questionnaire. Total leisure time activity per week was the basis of physical activity and was updated every 4 to 6 years. A food frequency questionnaire was used to report diet, and diet was reevaluated every other questionnaire cycle. An energy-adjusted DASH diet score was derived based on adherence to the DASH guidelines. Hazard ratios and 95% confidence intervals for the association between each lifestyle factor and chronic hypertension by history of HDPs were estimated using multivariable Cox proportional hazards models, stratified by questionnaire cycle and age. Associations were modeled separately in 3 age categories (32–39, 40–29, and 50–59 years) in order to correctly estimate effect modification by lifestyle from the Cox models. At study entry, 10% of women (n = 5520) had a history of HDPs in any pregnancy. Health, Inc. All rights reserved. 702 Obstetrical and Gynecological Survey In all, 13,971 cases of hypertension occurred during 689,988 person-years of follow-up. A higher cumulative incidence of chronic hypertension was observed for women with previous HDPs and low normal weight (BMI 18.5–22.4 kg/m) than for women without HDPs of the same weight, but that incidence was less than that of women with obesity class I (BMI 30.0–34.9 kg/m) without a history of HDPs. Basic cumulative incidence of chronic hypertension seemed to be higher in women with a history of HDPs than in women without HDPs for the lifestyle factors other than BMI, regardless of lifestyle. The study results indicate that BMI in the years after pregnancy modifies the association between previous HDPs and risk of chronic hypertension in women. No clear evidence was found of effect modification by physical activity, DASH diet, or sodium/potassium intake on either the additive or multiplicative scale. Overall, the present study found an association between overweight and obesity and increased risk of chronic hypertension in women with and without a history of hypertensive pregnancy. Women with both overweight/obesity and history of HDPs had higher than expected risk of chronic hypertension, given the risks observed with these risk factors were considered separately. These observations provide evidence for targeted clinical screening and interventions in these women, to potentially reduce the risk of chronic hypertension. The authors suggest that effective clinical interventions to facilitate a healthy lifestyle and weight postpregnancy are necessary to help reduce cardiometabolic risk in women with a history of HDPs and that clinicians should especially help women with a history of HDPs or gestational diabetes mellitus (GDM) mellitus to attain and maintain a healthy weight after pregnancy.