Association between duration of oral contraceptive use and risk of hypertension: A meta-analysis

A meta-analysis was conducted to evaluate the association between duration of oral contraceptive use and risk of hypertension. Relevant studies published in English or Chinese were identified by a search of PubMed, Web of Science, Wanfang Database, and China National Knowledge Infrastructure to January 2017. Seventeen articles containing 24 studies with 270,284 participants were included in this meta-analysis. The pooled relative risk of hypertension for the highest vs lowest category of oral contraceptive duration was 1.47 (95% confidence interval, 1.25-1.73), and excluding three studies with a relative risk >3.0 yielded a pooled relative risk of 1.26 (95% confidence interval, 1.11-1.44). A linear dose-response relationship was found (P-nonlinearity=0.69) and the risk of hypertension increased by 13% (relative risk, 1.13; 95% confidence interval, 1.03-1.25) for every 5-year increment in oral contraceptive use. The duration of oral contraceptive use was positively associated with the risk of hypertension in this meta-analysis.