Association between alkaline phosphatase and hypertension in a rural Japanese population: The Nagasaki Islands study

BACKGROUND: Although serum alkaline phosphatase (ALP) levels have been associated with hypertension, and ALP is known as an enzyme affected by alcohol consumption, no study has been published on the associations between ALP and the risk of hypertension in relation to drinking status. METHODS: We conducted a cross-sectional study of 2,681 participants (837 men and 1,846 women) aged 30 to 89 years undergoing a general health check-up to investigate the associations between ALP and hypertension in relation to drinking status. RESULTS: Of the 2,681 participants, 1,549 (514 men and 1,035 women) were diagnosed with hypertension. A sex difference was observed for the relationship between ALP and hypertension. While no significant association was observed for men, the association was significantly positive for women. The multivariable adjusted odds ratio and 95% coincidence interval (CI) of hypertension per increment of 1-log ALP were 0.95 (95% CI: 0.56 to 1.59) for men and 1.57 (95% CI: 1.07 to 2.33) for women. When this analysis was restricted to nondrinkers, a significantly elevated risk of hypertension was observed for men and remained significant for women; that is, 3.32 (95% CI: 1.38 to 8.02) for men and 1.68 (95% CI: 1.11 to 2.55) for women. CONCLUSION: ALP is associated with hypertension for both male and female nondrinkers, but not for drinkers. For analyses of associations between ALP and blood pressure, alcohol consumption should thus be considered a potential confounder.