Association between dietary magnesium intake and risk of hypertension in Chinese adults

BackgroundMagnesium plays an important physiological role in human, but the association between dietary magnesium intake and the risk of hypertension is unclear. Few studies have reported the dose-response relationship in Chinese population. ObjectiveTo analyze the relationship between dietary magnesium intake and the risk of hypertension in Chinese adults aged 18-64 years, and to explore the dose-response relationship. MethodsA total of 13082 adults aged 18-64 years who participated in at least two rounds of the China Health and Nutrition Survey (CHNS) from 2000 to 2018 were selected. Dietary data were obtained by consecutive 3-day 24-hour dietary recall and weighting & bookkeeping method. Blood pressure was measured with a standard mercury sphygmomanometer. Hypertension was diagnosed when systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg, or self-reported hypertension history or using antihypertensive drugs. The mean of dietary magnesium intake in all survey years (excluding the last survey) was used as the dietary magnesium intake of the subject, and the mean of dietary magnesium intake was divided into 5 equal groups. Cox proportional risk model with adjustments for socio-demographic factors, body mass index (BMI), smoking and drinking, sleep time, physical activity, and dietary factors, was used to analyze the association between dietary magnesium intake and the risk of hypertension. A sensitivity analysis was conducted by excluding baseline diabetes patients and adjusting for baseline blood pressure. In addition, a restricted cubic spline model was used to analyze the dose-response relationship between them. ResultsIn this study, male participants accounted for 47.70%, and those aged 18-44 years accounted for 72.47%. The mean follow-up time was 12.56 years and the prevalence of hypertension was 13.86%. Dietary magnesium intake was inversely associated with the risk of hypertension at the 4th quintile (median 333.56 mg·d−1) and the 5th quintile (median 420.07 mg·d−1) compared with the 1st quintile (median 189.06 mg·d–1), and the hazard risk (HR) values and associated 95%CIs were 0.81 (0.67-0.97) and 0.81 (0.66-0.99) respectively. After eliminating baseline diabetes and adjusting baseline blood pressure, dietary magnesium intake remained negatively associated with the risk of hypertension, which was consistent with the population-wide HR. The association between dietary magnesium intake and the risk of hypertension was non-linear (χ2=11.07, P=0.01). When dietary magnesium intake was higher than 339 mg·d−1, the risk of hypertension decreased, and the HR value was the lowest in 375-418 mg·d−1 (HR=0.65, 95%CI: 0.45-0.94), and then gradually tended to 1. There was no statistically significant association at 467 mg·d−1 and above.ConclusionMagnesium intake in the range of 339-467 mg·d−1 is negatively associated with the risk of hypertension in Chinese adults, presenting a U-shaped dose-response relationship.