[Concentration of 25-hydroxyvitamin D in postmenopausal women with low bone mineral density]

Suppression of Parathyroid Hormone as a Proxy for Optimal Vitamin D Status: Further Analysis of Two Parallel Studies in Opposite Latitudes

Optimal vitamin D status has commonly been defined as the level of 25-hydroxyvitamin D (25(OH)D) at which parathyroid hormone (PTH) concentrations would be maximally suppressed, represented by an observed minimum plateau. Previous findings indicate a large variation in this plateau, with values ranging from <30 nmol/L up to 100 nmol/L. This disparity in values might be explained by differences in study design and methodology, ethnicity, age, gender and latitude. This study aimed to investigate the concentration of 25(OH)D at which PTH concentrations were suppressed in Brazilian women living in opposite latitudes (high vs. low: i.e., UK and Brazil), during wintertime. Using data from the D-SOL study (Interaction between Vitamin D Supplementation and Sunlight Exposure in Women Living in Opposite Latitudes), the association between 25(OH)D status and PTH levels were examined in 135 Brazilian women (56 living in England and 79 living in Brazil, aged 20–59 years old). Mean PTH concentrations for Brazilian women with vitamin D deficiency (<25 nmol/L) were significantly higher compared to those with vitamin D insufficiency (25–49.9 nmol/L) (p < 0.01), vitamin D adequacy (50–74.9 nmol/L) (p < 0.01) and those with optimal vitamin D status (>75 nmol/L) (p < 0.001). Regression modelling was used to investigate the relationship between serum 25(OH)D and PTH for the sample as a whole and for each group separately. A cubic model was statistically significant for the total sample (p < 0.001), whereas a linear model presented the best fit for Brazilian women living in England (p = 0.04) and there were no statistically significant models fitted for Brazilian women living in Brazil. The cubic model suggests that 25(OH)D concentrations above 70–80 nmol/L are optimal to suppress the parathyroid gland in Brazilian women. These findings contribute to a better understanding of the relationship between 25(OH)D and PTH in populations living in a low latitude location and are of great relevance for discussions regarding the estimation of optimal cut-offs for vitamin D levels in the Brazilian population as well as for other low latitude locations.

The influence of the Pilates method on quality of life and bone remodelling in older women: a controlled study

PURPOSE

The objective of this study was to evaluate the effects of the Pilates method on quality of life and bone remodeling markers in a group of older women.

METHODS

A longitudinal prospective study with intervention was performed on 40 women aged over 60 years; they were divided into two groups: one submitted to a 50-min Pilates exercise session once a week for 20 weeks (Pilates), and the other was not (Control). Both groups were compared for quality of life using the Medical Outcomes Study 36, and for bone-specific alkaline phosphatase (BSAP) and Type 1 collagen C-telopeptide (CTx) bone remodeling markers.

RESULTS

The Pilates group presented improvement in the quality of life evaluation scores: physical functioning (67.50 ± 18.88 × 86.25 ± 9.58; p = 0.0232), and physical component summary (65.00 ± 14.39 × 79.70 ± 3.83; p = 0.0220). The Pilates group also presented higher scores than that of Controls after the exercise program: physical functioning (86.25 ± 9.58 × 55.50 ± 20.83, p = 0.0003), physical role (100.00 ± 0.00 × 41.25 ± 46.79, p = 0.0009), emotional role (100.00 ± 0.00 × 48.33 ± 50.12, p = 0.0046), vitality (82.50 ± 14.28 × 60.25 ± 21.43, p = 0.011), physical component summary (79.70 ± 3.83 × 54.90 ± 15.05, p < 0.0001), and emotional component summary (74.10 ± 8.37 × 54.18 ± 22.55, p = 0.0111). No changes were noted in bone remodeling markers [CTx (0.39 ± 0.26 × 0.38 ± 0.22 ng/mL) and BSAP (10.73 ± 2.40 × 11.01 ± 3.56 μg/L)] and did not differ from the Control group both before (CTx: 0.39 ± 0.26 × 0.37 ± 0.17 ng/mL; BSAP: 10.73 ± 2.40 × 10.58 ± 3.49 μg/L; p > 0.05) and after exercise (CTx: 0.38 ± 0.22 × 0.38 ± 0.22 ng/mL; BSAP: 11.01 ± 3.56 × 9.85 ± 3.12 μg/L; p > 0.05).

CONCLUSION

The group of women submitted to Pilates presented improved quality of life but without changes in bone remodeling.

Sun exposure, skin lesions and vitamin D production: evaluation in a population of fishermen

BACKGROUND

Exposure to UVR provides benefits related to vitamin D synthesis, but also causes harms, since UVB is considered a complete carcinogen. There is no definition of the level of sun exposure and the proportion of exposed body required for proper synthesis of vitamin D in the skin without causing it damage.

OBJECTIVES

This study aims to analyze the sun exposure index, vitamin D levels and clinical changes in the skin caused by constant sun exposure in the fishermen population.

METHODS

It is a cross-sectional, observational and analytical study. The sample consisted of fishermen and was calculated in 174 individuals. The questionnaire was applied, the dermatological examination was carried out and the examinations of calcidiol, parathyroid hormone, calcium and phosphorus were requested. Data were expressed as percentages. The comparative analysis was done through the Chi-square test, and the correlations were established through the Pearson's linear coefficient. Results: We observed that there was vitamin D deficiency in a small part of the cases (11.46%), and the frequency of diagnosis of skin cancer was 2.7% of the cases surveyed.

STUDY LIMITATIONS

The difficulty in categorizing the sun exposure index.

CONCLUSION

The fact that fishermen expose themselves to the sun chronically and have been exposed to the sun for more than 15 years, between 21 and 28 hours a week, and without photoprotection, were indicative factors for protection against vitamin D deficiency. Chronic exposure to sun and high vitamin levels D may be indicative of protection of this population against skin cancer.

Association between 25-Hydroxyvitamin D, Parathyroid Hormone, Vitamin D and Calcium Intake, and Bone Density in Healthy Adult Women: A Cross-Sectional Analysis from the D-SOL Study

There is still limited data on the association between 25-hydroxyvitamin D (25(OH)D), parathyroid hormone (PTH), and bone health in healthy younger adults, particularly in Latin America. This cross-sectional analysis aimed to investigate the associations of 25(OH)D and plasma PTH concentrations with bone parameters, and potential confounders, in women living in a high (England) or low (Brazil) latitude country. Bone was assessed by either peripheral quantitative computed tomography (pQCT) (England) or dual-energy x-ray absorptiometry (DXA) scan (Brazil), serum 25(OH)D concentrations by high performance liquid chromatography tandem mass spectrometry (HPLC-MS) and PTH by the chemiluminescent method. In participants living in England, total volumetric bone mineral density (vBMD) was significantly higher in women <29 years compared to ≥30 years, and total and cortical vBMD values at the 66% site were negatively correlated with weight and body mass index (BMI). In participants living in Brazil, age was positively correlated with bone mineral density (BMD) at the femur and bone mineral content (BMC), and weight, BMI, and body fat were correlated with BMD (lumbar spine and femur) and BMC. PTH concentrations were negatively correlated with 25(OH)D concentrations, and the prevalence of secondary hyperparathyroidism was 28.6% (n = 14) in participants with concentrations <25 nmol/L and 12.2% (n = 41) with concentrations between 25 and 49.9 nmol/L, compared to 6.3% (n = 79) in those with concentrations ≥50 nmol/L. In conclusion, weight and BMI were significantly correlated with bone parameters in both groups and age was significantly correlated with BMD at the femoral neck for women living in Brazil only. Although 25(OH)D concentrations were not correlated to bone parameters at any sites, in either country, PTH concentrations showed a significant correlation with total vBMD at the 66% site for women living in England. Secondary hyperparathyroidism was more common amongst those with deficient and insufficient vitamin D status.

Body composition and nutritional and metabolic parameters in postmenopausal women sufficient, insufficient and deficient in vitamin D

OBJECTIVE

We investigated changes in body composition and nutritional and metabolic parameters in a group of postmenopausal women who were classified as sufficient, insufficient and deficient in vitamin D.

SUBJECTS AND METHODS

A total of 106 postmenopausal women were included in this cross-sectional study and classified according to their serum levels of 25-OH-vitamin D as sufficient (≥ 30 ng/mL; group S), insufficient (20.1 and 29.9 ng/mL; group I) or deficient (≤ 20 ng/mL; group D) in vitamin D. Body composition was measured by dual-energy X-ray absorptiometry (DXA); dietary recall questionnaires were completed; and blood samples were analysed to compare the metabolic and nutritional status of the study groups.

RESULTS

Eleven (10.4%) of the women were classified in group S, 50 (47.2%) in group I and 45 (42.4%) in group D, with a mean serum level for 25-OH-D of 21.1 ± 7.0 ng/mL in all participants. Body composition did not differ among the groups. Serum levels of 25-OH-D were negatively correlated with serum levels of triglycerides, total cholesterol and LDL cholesterol.

CONCLUSIONS

Vitamin D insufficiency and deficiency were highly prevalent in our group of postmenopausal women, showing an association with an unfavourable lipid profile.

Elderly with proximal hip fracture present significantly lower levels of 25-hydroxyvitamin D

OBJECTIVE

To compare serum 25-hydroxyvitamin D (25[OH]D) levels, a serum marker of vitamin D3, between patients with and without proximal hip fracture.

METHODS

This was a case-control study in which serum samples of 25(OH)D were obtained from 110 proximal hip fracture inpatients and 231 control patients without fractures, all over 60 years of age. Levels of 25(OH)D lower than or equal to 20 ng/mL were considered deficient; from 21 ng/mL to 29 ng/mL, insufficient; and above 30 ng/mL, sufficient. Sex, age, and ethnicity were considered for association with the study groups and 25(OH)D levels.

RESULTS

Patients with proximal hip fracture had significantly lower serum 25(OH)D levels (21.07 ng/mL) than controls (28.59 ng/mL; p = 0.000). Among patients with proximal hip fracture, 54.5% had deficient 25(OH)D levels, 27.2% had insufficient levels, and only 18.2% had sufficient levels. In the control group, 30.3% of patients had deficient 25(OH)D levels, 30.7% had insufficient levels, and 38.9% had sufficient levels. Female patients had decreased serum 25(OH)D levels both in the fracture group and in the control group (19.50 ng/mL vs. 26.94 ng/mL; p = 0.000) when compared with male patients with and without fracture (25.67 ng/mL vs. 33.74 ng/mL; p = 0.017). Regarding age, there was a significant association between 25(OH)D levels and risk of fracture only for the age groups 71-75 years and above 80 years.

CONCLUSION

Patients with proximal hip fracture had significantly decreased serum 25(OH)D levels when compared with the control group. Female patients had significantly lower serum 25(OH)D levels in both groups.

Vitamin D status among healthy postmenopausal women in South America

Vitamin D status has been extensively studied throughout the world. However, most of the studies are from North America, Europe and Oceania. This review describes published evidence on vitamin D status among healthy postmenopausal women in South America, where food is not fortified with vitamin D. A literature search identified ten studies from only three countries in the region: Argentina, Brazil and Chile. These studies reported a high prevalence of vitamin D deficiency, in spite of their location at latitudes with abundant sunlight throughout the year. In studies with proper design, a clear North-South gradient was revealed with higher 25(OH)D levels toward the equator. Seasonal changes in 25(OH)D were more likely to be detected in younger subjects. These results are very similar to what has been reported in the Northern Hemisphere and they emphasize the importance of recommendations for a higher vitamin D intake in this population from South America.

Association of back pain with hypovitaminosis D in postmenopausal women with low bone mass

Background

Back pain is a major public health problem due to its high frequency, to the resulting activity constraint, and the need for surgery in many cases. Back pain is more frequent in women than men, mainly in postmenopausal women. High prevalence of hypovitaminosis D has been detected in postmenopausal women, and it is associated with decreased bone mass, sarcopenia, vertebral fractures, and inflammation, which can be related to back pain.

Methods

The relation between back pain and hypovitaminosis D was evaluated in this study, as well the difference regarding the number of bedridden days, number of days away from work, and daily activities limitation between women with and without hypovitaminosis D. This study reviewed baseline data from an interventional phase III multicenter trial in low bone mass postmenopausal women. The study included demographic data, 25OHD determinations, Newitt/Cummings questionnaire on back pain, and vertebral fracture identified thought X-ray evaluation.

Results

The trial included 9354 participants, but only 9305 underwent all the evaluations. The age median was 67 (60 - 85 years old) and age at menopause was 49 (18 - 72 years). Hypovitaminosis D was found in 22.5% of the subjects, 15.3% of them had vertebral fractures, 67.5% with back pain, and 14.8% reduced their daily activities in the previous six months. Subjects with hypovitaminosis D, compared to those without hypovitaminosis D, reported more back pain (69.5 v 66.9%, p: 0.022), more cases of severe back pain (8.5% v 6.8%, p: 0,004), higher limitation in their daily activities (17.2 v 14.0%, p: 0.001), and more fractures (17.4 v 14.6%, p: 0,002); also, they had more trouble to perform daily activities addressed in the Newwit/Cummings questionnaire.

Conclusion

Hypovitaminosis D was related to back pain, to its severity, and to difficulty in perform daily activities.

Trial registration

ClinicalTrial.gov: NCT00088010