Association of vitamin D receptor polymorphism with calcaneal broadband ultrasound attenuation in Korean postmenopausal women with low calcium intake.

This study investigated the associations among vitamin D receptor (VDR) BsmI polymorphism, calcium intake and bone strength as indicated by the broadband ultrasound attenuation (BUA) measured by calcaneal quantitative ultrasound at the left calcaneus in community-dwelling subjects with a low calcium intake. The VDR BsmI polymorphism was analysed in 335 women older than 65 years residing in rural Asan, Korea. Calcium intake was assessed with a 2 d, 24 h recall method. The distribution of genotypes was similar to that reported in other Asian populations (92 % bb, 7 % Bb and 1 % BB). The calcaneal BUA was significantly higher (P = 0.013) in the bb genotype than in the Bb or BB genotype (Bb and BB genotypes were combined due to the small number of BB subjects) in a multiple regression model after adjusting for age, body weight, height, physical activity and nutritional factors. BUA was not significantly affected by the calcium intake regardless of the genotype, cross-sectionally. The energy-adjusted average calcium intake of this population was 439.6 mg/d (432.5 mg/d for bb and 522.3 mg/d for Bb or BB), and 96 % of the subjects had dietary intakes that were less than the recommended Dietary Reference Intake for Koreans (which for calcium is 800 mg/d for women older than 65 years). In summary, the BUA in older Korean women with a low calcium intake was significantly influenced by the VDR genotype but not by the calcium intake, cross-sectionally.