The data on of alimentary risk factors of osteoporosis have been observed. The frequency of decreased bone mineral density, vitamin and calcium diet content and sufficiency with vitamins evaluated by means of blood serum level determination among patients suffering from chronic diseases (of cardiovascular system, gastrointestinal tract, osteopenia and osteoporosis).
Several factors may increase fracture risk, among them reduced bone mineral density (BMD), increased bone resorption, microarchitectural deterioration of bone, increased fall risk, and decreased muscle strength. We have previously reported that PvuII polymorphism of the estrogen receptor-alpha (ER alpha) gene is associated with bone loss rate, fracture risk, and response to hormone replacement therapy (HRT) in early postmenopausal Finnish women.
We studied the influence of the ER alpha genotype on fall risk and muscle strength in a 5-year randomized HRT trial of 331 early postmenopausal women (subgroup of the population-based OSTPRE study, Kuopio, Finland). A 5-year postal inquiry in May 1994 included questions on falls during the previous 12 months. Grip strength was measured with dynamometer. The ER alpha gene polymorphism was analysed using PCR and PvuII restriction enzyme digestion. RESULTS. In all, 97 out of the 331 women reported falls. Half of those (56%) were slip falls, mostly during the winter season. In the HRT group, the ER alpha genotype was associated with fall risk (P = 0.002, logistic regression). The risk of falls (RR) was higher in women with the PP genotype than in those with the Pp (RR = 5.26, 95% CI 1.98-13.94, P = 0.001) or the pp (RR = 3.84, 95% CI 1.46-10.12, P = 0.007) genotype. When the falls were divided into slip (environment-related) and non-slip (endogenous) falls, the non-slip falls were associated with the genotype (P = 0.004), but the slip falls were not so clearly (P = 0.061). When all falls and non-slip falls were adjusted to the number of chronic health disorders and the variable time-since-menopause, the difference between the genotypes persisted (P = 0.003 and P = 0.010, respectively). In the non-HRT group, the ER alpha genotype was not associated with fall risk. The baseline or the 5-year grip strength values were not influenced by the ER alpha genotype. In conclusion, ER alpha polymorphism is associated with fall risk, especially with non-slip falls, in early postmenopausal Finnish women during the HRT. We have previously reported that, during HRT, women with the P allele have decreased fracture risk and that they may preferentially derive benefit from the positive effect of HRT on BMD. This suggests that the influence of ER alpha polymorphism may depend on the target tissue (bone versus the nervous system).
In these early postmenopausal, non-osteoporotic and relatively healthy women, the increased fall risk associated with the PP genotype was not associated with increased fracture risk, possibly due to improved bone strength during the HRT although falls generally predispose to fractures.
Peak bone mass is a major determinant of osteoporosis risk in later life. It is under strong genetic control; however, little is known about the identity of the genes involved. In the present study, we investigated the relationship between polymorphisms in the genes encoding the vitamin D receptor (VDR) (FokI, TaqI) and estrogen receptor-alpha (ERalpha) (PvuII, XbaI), and bone mineral density (BMD), bone mineral content (BMC), and markers of bone turnover in 224 Danish girls aged 11-12 years. BMD and BMC were measured by dual-energy X-ray absorptiometry. Serum osteocalcin, 25(OH)D, and parathyroid hormone (PTH) were measured by ELISA assays and urinary pyridinium cross-links by HPLC. Physical activity, dietary calcium, and Tanner stage were assessed by questionnaire. In general, there were no significant differences in anthropometrical variables, physical activity, dietary calcium, serum 25(OH)D, or PTH among genotype groups. BMD or BMC of lumbar spine or whole body (adjusted for body and bone size and pubertal status) were not associated with VDR or ERalpha genotypes or the combination of these genotypes. This lack of association remained even after adjustment for dietary and environmental factors. VDR genotypes had no effect on bone turnover markers. XX and PP ERalpha genotypes were associated (P