A large percentage of adolescent females have low vitamin D status during the winter in Finland, which seems to have negative effects on bone health.

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Excessive dietary P intake alone can be deleterious to bone through increased parathyroid hormone (PTH) secretion, but adverse effects on bone increase when dietary Ca intake is low. In many countries, P intake is abundant, whereas Ca intake fails to meet recommendations; an optimal dietary Ca:P ratio is therefore difficult to achieve. Our objective was to investigate how habitual dietary Ca:P ratio affects serum PTH (S-PTH) concentration and other Ca metabolism markers in a population with generally adequate Ca intake. In this cross-sectional analysis of 147 healthy women aged 31-43 years, fasting blood samples and three separate 24-h urinary samples were collected. Participants kept a 4-d food record and were divided into quartiles according to their dietary Ca:P ratios. The 1st quartile with Ca:P molar ratio #0·50 differed significantly from the 2nd (Ca:P molar ratio 0·51 -0·57), 3rd (Ca:P molar ratio 0·58 -0·64) and 4th (Ca:P molar ratio $ 0·65) quartiles by interfering with Ca metabolism. In the 1st quartile, mean S-PTH concentration (P¼ 0·021) and mean urinary Ca (U-Ca) excretion were higher (P¼ 0·051) than in all other quartiles. These findings suggest that in habitual diets low Ca:P ratios may interfere with homoeostasis of Ca metabolism and increase bone resorption, as indicated by higher S-PTH and U-Ca levels. Because low habitual dietary Ca:P ratios are common in Western diets, more attention should be focused on decreasing excessively high dietary P intake and increasing Ca intake to the recommended level.Ca:P ratio: Parathyroid hormone: Ca metabolism: P intake: Ca intake

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Objective: The study was designed to evaluate the vitamin D status in women of different physiological status of two socioeconomic groups in Bangladesh. Design: A cross-sectional study, using serum 25-hydroxyvitamin D (25-OHD), calcium, phosphorus and alkaline phosphatase activity. Setting: Two regions of Bangladesh. The Dhaka city area and west region of Nandail (Betagair Union), Mymensingh. Subjects: Representative subjects of two groups (low socio-economic group ¼ group L, n ¼ 99; and high socio-economic group ¼ group H, n ¼ 90) of Bangladeshi women aged 16 -40 y. About 87% of the subjects were housewives and the rest, 13%, were distributed among other different professions. Each group comprised of three sub-groups (non-pregnant nonlactating ¼ 1, pregnant ¼ 2, and lactating ¼ 3). Results: The influence of socio-economic status and physiological status on serum 25-OHD concentration (P ¼ 0.038, P ¼ 0.015, respectively), serum calcium concentration (P < 0.001, P < 0.001, respectively) and alkaline phosphatase activity (P < 0.001, P < 0.001, respectively) were observed. The distribution of serum 25-OHD concentration in both groups was shifted overall toward the lower limit of the normal range. Seventeen percent of women in group L and 12% of women in group H had serum 25-OHD concentration < 25 nmol=l. Hypovitaminosis D (serum 25-OHD concentration 37.5 nmol=l) was observed in 50% of subjects in group L and 38% of subjects in group H, respectively. The prevalence of hypovitaminosis was higher in lactating subjects of the groups L and H (63 and 46%, respectively) than in the other sub-groups in the same group. Conclusions: The results of the study suggested that women in Bangladesh were at risk of hypovitaminosis D and lactation was an additional risk factor in low income groups. The situation may increase the risk of bone loss.