Low Calcium Intake in Midpregnancy Is Associated with Hypertension Development within 10 Years after Pregnancy
Background: Low dietary calcium intake may be a risk factor for hypertension, but studies conflict.
We evaluated the ability to predict hypertension within 10 y after delivery based on calcium intake during midpregnancy.
The Norwegian Mother and Child Cohort Study of women delivering in 2004–2009 was linked to the Norwegian Prescription Database (2004–2013) to ascertain antihypertensive medication usage >90 d after delivery. Women with hypertension before pregnancy were excluded, leaving 60,027 mothers for analyses. Age and energy-adjusted cubic splines evaluated dose-response curves, and Cox proportional hazard analyses evaluated HR and 95% CIs by calcium quartiles adjusting for 7 covariates. Analyses were stratified by gestational hypertension and by sodium-to-potassium intake ratio (<0.76 compared with ≥0.76).
Participants had a mean ± SD age of 30.5 ± 4.6 y, a body mass index (in kg/m2) of 24.0 ± 4.3 before pregnancy, and a mean follow-up duration of 7.1 ± 1.6 y. Cubic spline graphs identified a threshold effect of low calcium intake only within the range of dietary inadequacy related to increased risk. The lowest calcium quartile (≤738 mg/d; median: 588 mg/d), relative to the highest quartile (≥1254 mg/d), had an HR for hypertension of 1.34 (95% CI: 1.05, 1.70) among women who were normotensive during pregnancy, and an HR of 1.62 (95% CI: 1.14, 2.35) among women who had gestational hypertension, after adjusting for covariates. Women with gestational hypertension, who were in the lowest quartile of calcium intake, and who had a high sodium-to-potassium intake ratio had a risk of hypertension more than double that of their counterparts with a calcium intake in the highest quartile. Results were attenuated by adjusting for covariates (HR: 1.92; 95% CI: 1.09, 3.39).
The results suggest that low dietary calcium intake may be a risk factor or risk marker for the development of hypertension, particularly for women with a history of gestational hypertension.
- Forfattere: Egeland, Grace M; Skurtveit, Svetlana; Sakshaug, Solveig; Daltveit, Anne Kjersti; Vikse, Bjørn Egil; Haugen, Margaretha.
- Publisert: Journal of Nutrition 2017