Dyslipidaemia, combined oral contraceptives use and their interaction on the risk of hypertension in Chinese women.

The objective of the study was to assess the associations of dyslipidaemia, combined oral contraceptive (COC) use and their interaction on the risk of hypertension in Chinese women. In a case-control study, we evaluated 665 hypertensive women and 665 normotensive women matched on region and age in China. Hypertensive women had a higher prevalence of dyslipidaemia and higher levels of total cholesterol, triglyceride, low-density lipoprotein-cholesterol and lipoprotein a than normotensive ones (P<0.05). The risk of hypertension gradually increased with the increasing cumulative time of COC use in women (P=0.0043), especially significantly increased among those with cumulative time of COC use 15-20 and ≥20 years (adjusted odds ratio (OR)=1.46, 95% confidence interval (CI): 1.00-2.15; OR=1.49, 95% CI: 1.06-2.11), but gradually decreased from stopping use of COC (P<0.0001). The multiplicative interaction between dyslipidaemia and accumulative time of COC use ≥15 years, dyslipidaemia and family history of hypertension, or family history of hypertension and accumulative time of COC use ≥15 years was confirmed and the interaction analyses showed that they can significantly increased the risk of hypertension (adjusted OR=2.82, 95% CI: 1.59-3.27; OR=4.33, 95% CI: 3.10-6.06; OR=4.56, 95% CI: 3.07-6.77). It is concluded that dyslipidaemia, accumulative time of COC use ≥15 years and their interaction increased the risk of hypertension.