Salivary bone turnover markers in healthy pre- and postmenopausal women: daily and seasonal rhythm.

No studies had investigated circadian and circannual rhythms of bone biomarkers in whole saliva. We evaluated the salivary daily and seasonal rhythm of carboxy-terminal telopeptide of type I collagen (CTX) and bone alkaline phosphatase (b-ALP). Forty clinical and oral healthy ambulatory pre- and postmenopausal women from two southern Argentine cities: Comodoro Rivadavia (latitude 45º S) and Ushuaia (latitude 54º S) were included in the study. CTX levels were evaluated in serum, urine, and saliva, and b-ALP levels were measured in serum and saliva. In both groups of women, salivary CTX showed a maximum percentage of change early in the morning (80%) and a minimum in the late afternoon (45%), similarly to the pattern observed in urinary samples. No daily rhythm was observed in serum or salivary b-ALP. 25-Hydroxyvitamin D levels decreased in winter vs. summer (p < 0.01) without differences between the two studied groups. Conversely, parathormone reached higher levels in winter (p < 0.05) which induced a slight non-significant increment in salivary CTX and b-ALP levels. The results showed that, as in serum and urinary samples, salivary CTX exhibits daily and a slight seasonal rhythmicity. Whole non-stimulated saliva is a useful tool to detect several oral and systemic diseases because it has important advantages compared to serum and urinary samples. Then, it may also be a promising sample to test changes in bone metabolism contributing to diagnose and to monitor the therapy of several metabolic bone diseases.

Risk factors for decreased bone density in premenopausal women

Osteoporosis is a major health problem. Little is known about the risk factors in premenopause. Sixty 40-50 year old patients with regular menses were studied cross-sectionally. None of the patients were on drugs known to interfere with bone mass. Patients answered a dietary inquiry and had their bone mineral density (BMD) measured. The Z scores were used for the comparisons. A blood sample was taken for the determination of FSH, SHBG, estradiol, testosterone, calcium and alkaline phosphatase. Calcium and creatinine were measured in 24-h urine. A Z score less than -1 was observed for the lumbar spine of 14 patients (23.3 percent), and for the femur of 24 patients (40 percent). Patients with a Z score less than -1 for the lumbar spine were older than patients with a Z score ò-1 (45.7 vs 43.8 years) and presented higher values of alkaline phosphatase (71.1 + 18.2 vs 57.1 + 14.3 IU/I). Multiple regression analysis showed that a lower lumbar spine BMD was associated with higher values of alkaline phosphatase, lower calcium ingestion, a smaller body mass index (BMI), less frequent exercising, and older age. The patients with a Z score less than -1 for the femur were shorter than patients with a Z score ò-1 (158.2 vs 161.3 cm). Multiple regression analysis showed that a lower femoral BMD was associated with lower BMI, higher alkaline phosphatase and caffeine intake, and less frequent exercising. A lower than expected BMD was observed in a significant proportion of premenopausal women and was associated with lower calcium intake, relatively lower physical activity and lower BMI. We conclude that the classical risk factors for osteoporosis may be present before ovarian failure, and their effect may be partly independent of estrogen levels.