Seasonal variation in bone metabolism in young healthy subjects

Abstract

Serum vitamin D metabolites and urinary calcium excretion; parameters of bone formation (serum alkaline phosphatase, serum osteocalcin); parameters of bone resorption (24 hour hydroxyprolinuria, 2 hour fasting urinary hydroxyproline/creatinine ratio); and parameters of cortical and trabecular bone density, parathyroid hormone (iPTH, COOH terminal assay), and serum minerals (calcium, phosphorus) were followed serially in 55 young adults (21 women and 34 men) from December 1985 until January 1987 at four different times during the year. The effect of a low-dose cyclooxygenase inhibitor (piroxicam 5 mg daily) on the same parameters of bone density and bone turnover when given from December until May, was also evaluated in this study. At the end of the treatment period parameters of bone turnover and bone density were comparable between placebo and piroxicam-treated groups. Therefore, the results of all subjects were pooled in order to investigate seasonal variation. In both sexes, seasonal variation was found not only for 250HD3 but also for 1,25(OH)2D3, serum calcium and phosphorus, urinary calcium excretion, and for bone density at the lumbar spine. Parameters of bone formation (serum osteocalcin and alkaline phosphatase), bone resorption (24 hour urinary hydroxyprolinuria and fasting urinary hydroxyproline/creatinine ratio) and PTH were influenced by this seasonal variation. We conclude that in young adults, a significant seasonal variation occurs, with low winter and high summer values, for serum 25 and 1,25(OH)2D3 for urinary calcium apparently without important influence on parameters of bone turnover or parathyroid activity and for lumbar spine density. Treatment with a low-dose cyclooxygenase inhibitor was without influence on the observed changes.

Seasonal variations in vitamin D status and calcium absorption do not influence bone turnover in young women

“…Maintenance of serum calcium can be made by bone mineralization andaor increased loss. As shown in Table 3, 24 h urinary excretion was enhanced during summertime thereby con®rming previous studies on the in¯uence of season on urinary calcium excretion (Robertson et al, 1974;Vanderschueren et al, 1991). Phosphorus excretion resembled that of calcium with higher values in summer and lower in winter (Table 3).…”

“…Variations in serum 25OHD and urinary calcium secretion but no change in alkaline phosphatase, serumosteocalcin (biomarkers of bone formation) and urinary hydroxyproline (biomarker of bone resorption) have been observed in young males and females (Vanderschueren et al, 1991). A reduction in serum 25OHD of young subjects during wintertime has been found in several studies in western and northern Europe (McKenna, 1992).…”

A seasonal variation of calcitropic hormones, bone turnover and bone mineral density in early and mid-puberty girls – a cross-sectional study

“…Seasonal variation of bone mineral density, bone mineral content and bone size Earlier studies have reported seasonal variation in bone mass in different populations (Bergstralh et al 1990;Dawson-Hughes & Harris, 1993;Rosen et al 1994;Rapuri et al 2002) but others have not found such a variation (Vanderschueren et al 1991;Tsai et al 1997;Overgaard et al 1998). We stated a 7·5 -8·2 % seasonal variation in site-specific BMD in early puberty girls, which seems to be somewhat higher than observed in healthy adults (Bergstralh et al 1990;Dawson-Hughes & Harris, 1993).…”

“…In separate groups, U-DPyr and U-Pyr did not follow the seasonal rhythm. In follow-up studies resorptive bone markers tend to increase during winter ( Vanderschueren, 1991;Rosen et al 1994;Woitge et al 2000;Rapuri et al 2002;Lehtonen-Veromaa et al 2002), due to increased parathyroid hormone secretion. Although S-iPTH increased throughout the winter among early puberty girls, we did not observe an increase in resorptive markers: the use of one time specimen to measure bone remodelling markers in a cross-sectional study is not informative, because of many confounding factors or due to a small sample size (e.g.…”

The seasonal importance of serum 25‐hydroxyvitamin D for bone mineral density in older women

“…In samples collected during summer, we found a gradual increase in BMD of the total hip up to a S-25OHD level of 40 nmol L À1 (6% of the cohort). In women with S-25OHD concentrations below 30 nmol L À1 during summer, adjusted BMD was 11% lower [95% confidence interval (CI) [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] and in those with S-25OHD levels of 30-40 nmol L À1 BMD was 6% lower (95% CI 1-11), compared with women with S-25OHD levels above 80 nmol L…”