[Recent progress in treatment of osteoporosis]

Osteoporosis is a multifactorial disease. Understanding the genetic and environmental background of this disease is essential for prevention and treatment. We examined the relationship between polymorphisms of the estrogen receptor gene, bone mineral density, and markers of boe metabolism in postmenopausal women. Restriction fragment length polymorphisms of the estrogen receptor (ER) gene and its relation to bone mineral density were examined in 238 postmenopausal healthy women (66.7 +/- 0.9 yr, mean +/- standard error of the mean) in Japan. In those with the PPxx genotype, Z score values of bone mineral density were significantly lower than those for other genotypes (lumbar spine; p = 0.005, total body; p = 0.013). Dinucleotide repeat polymorphisms in the upstream region of ER gene were related to bone mineral density and to bone metabolic markers. These data suggest that some variation of the ER gene linked to these genetic markers is associated with the pathogenesis of postmenopausal osteoporosis. In addition, we focused on the role of vitamin K as a nutritional factor for bone metabolism. Japanese fermented beans, Natto, contain larage amounts of vitamin K2. We found a significant positive correlation between the level of vitain K2 in serum and the habit of eating Natto in postmenopausal women in the Toyo area. Natto may contribute to the prevention of osteoporosis.