Evidence concerning the relation between dietary calcium intake and development of hypertension is inconsistent.

Some of this inconsistency may be due to interaction of this relation with other factors.

The current study was designed to test for an interaction between alcohol consumption and the relation of dietary calcium intake to 10-year incidence of hypertension in a sample of the US adult population : the Epidemiologic Follow-up Study (1982-1984) of the First National Health and Nutrition Examination Survey (NHANES I) (1971-1975).

Interactive logistic regression models were estimated with incident hypertension defined as self-reported treatment with antihypertensive medication.

After exclusion of participants with evidence of hypertension at baseline (resulting n=6,634), odds ratios for hypertension were estimated for each 1-g/day increase in calcium intake.

The relation between dietary calcium and incident hypertension showed significant interactions with frequency of alcohol use (odds ratio (OR)=1.33 for daily drinkers, OR=0.84 for others ; p=0.005 for difference), age (OR=0.75 for ¾40 years at baseline, OR=1.00 for>40 years ; p=0.004), and body mass index, defined as weight (kg) divided by height (m) squared (OR=0.82 for ¾26, OR=1.01 for>26 ; p=0.018).

Interactions with sex and race (black vs. white) were not significant (p = 0.4). (...)