American Indians have a high prevalence of obesity. Evidence supports a relationship between increased dietary calcium intake and lower body weight. This study was conducted to investigate the association between dietary calcium intake, BMI, and percentage of body fat (PBF) in American Indians (ages 47-79 y) in the Strong Heart Study (SHS) (2nd exam, 1992-1995). SHS data were compared with data for the general U.S. adult population from the NHANES III (1988-1994). BMI was calculated as kg/m(2). PBF was estimated by bioelectrical impedance using an equation based on total body water. The clinical examination included measures of blood chemistry. Dietary data were collected using a 24-h dietary recall. Calcium intake was significantly lower in SHS participants than in age-matched NHANES III participants. Mean calcium intake in the SHS was 680 mg/d (range: 103-4574 mg/d) for men and 610 mg/d (range: 71-4093 mg/d) for women (P < 0.001). After adjustment for potential confounders, BMI and PBF were lower by 0.80 kg/m(2) (95% CI: -1.53 to -0.08, P = 0.046) and 1.28% (95% CI: -2.10 to -0.47, P = 0.011) in SHS participants with higher (> or = 873 mg/d in the 5th quintile) vs. lower calcium intake (<313 mg/d in the 1st quintile). No relation between calcium intake and BMI or PBF was observed in NHANES III participants. Our data may be used to develop nutritional interventions aimed at weight control in culturally appropriate clinical trials.