RESUMEN
BACKGROUND: Air particulate matter (PM) is a ubiquitous environmental exposure associated with oxidation, inflammation, and age-related chronic disease. Whether PM is associated with loss of bone mineral density (BMD) and risk of bone fractures is undetermined. METHODS: We conducted two complementary studies of: (i) long-term PM <2.5 µm (PM2.5) levels and osteoporosis-related fracture hospital admissions among 9.2 million Medicare enrollees of the Northeast/Mid-Atlantic United States between 2003-2010; (ii) long-term black carbon [BC] and PM2.5 levels, serum calcium homeostasis biomarkers (parathyroid hormone, calcium, and 25-hydroxyvitamin D), and annualized BMD reduction over a 8-year follow-up of 692 middle-aged (46.7±12.3 yrs), low-income BACH/Bone cohort participants. FINDINGS: In the Medicare analysis, risk of bone fracture admissions at osteoporosis-related sites was greater in areas with higher PM2.5 levels (Risk ratio [RR] 1.041, 95% Confidence Interval [CI], 1.030, 1.051). This risk was particularly high among low-income communities (RR 1.076; 95% CI, 1.052, 1.100). In the longitudinal BACH/Bone study, baseline BC and PM2.5 levels were associated with lower serum PTH (Estimate for baseline one interquartile increase in 1-year average BC= -1.16, 95% CI -1.93, -0.38; Estimate for baseline one interquartile increase in 1-year average PM2.5= -7.39; 95%CI -14.17, -0.61). BC level was associated with higher BMD loss over time at multiple anatomical sites, including femoral neck (-0.08%/year per one interquartile increase; 95% CI -0.14, -0.02%/year) and ultradistal radius (-0.06%/year per one interquartile increase; 95% CI -0.12, -0.01%/year). INTERPRETATION: Our results suggest that poor air quality is a modifiable risk factor for bone fractures and osteoporosis, especially in low-income communities.
RESUMEN
Vitamin D deficiency is highly prevalent worldwide, and is linked to several major chronic, inflammatory and autoimmune diseases. Vitamin D deficiency has not been evaluated in dark skinned individuals living in areas of high sun exposure utilizing more reliable mass spectrometry assay techniques. We determined the prevalence of 25-hydroxyvitamin D (25(OH)D) deficiency in Afro-Caribbean men on the tropical island of Tobago, where there is a high level of sunshine year round. Serum 25(OH)D2 and 25(OH)D3 metabolites were measured following extraction and purification using liquid chromatography and tandem mass spectrometry in 424 Afro-Caribbean men aged > 65 years from a larger population-based cohort study. The mean (+/- SD) serum total 25(OH)D concentration was 35.1 +/- 8.9 ng/mL. Deficiency (< 20 ng/mL) was present in only 2.8% and insufficiency (< 30 ng/mL) in 24% of the men. Multiple linear regression analysis identified age, BMI and daily vitamin D supplementation as the independent correlates of 25(OH)D. None of the men who consumed fish more than once per week had vitamin D deficiency, compared to 4% of the men who consumed fish once per week or less (P = .01, adjusted for age, BMI, and daily vitamin D supplementation). In conclusion, vitamin D deficiency is very uncommon in this Afro-Caribbean population. Longitudinal studies are needed to delineate the possible effects of high vitamin D levels in this population on major diseases hypothesized to be associated with vitamin D deficiency.