ABSTRACT: Vitamin D, ultraviolets and skin cancer The vitamin D supply is fundamental for the prevention of falls and fractures in aged people, among other effects. UVB triggers vitamin D synthesis in the skin. This relationship has recently gained attention both with the general public and with health care professionals. Some authors suggest a relaxation of UV protection measures, while others even advocate regular sunlight exposure in order to increase cutaneous vitamin D synthesis. However, the UV irradiation responsible for vitamin D synthesis also is a known carcinogen. UV exposure is an insufficient and harmful method to increase vitamin D synthesis. Oral supplementation is the recommended way to prevent and cure vitamin D deficiency.
Revue médicale suisse 04/2010; 6(246):884-5.
ABSTRACT: Current intake recommendations of 200 to 600 IU vitamin D per day may be insufficient for important disease outcomes reduced by vitamin D.
This study assessed the benefit of higher-dose and higher achieved 25-hydroxyvitamin D levels [25(OH)D] versus any associated risk.
Based on double-blind randomized control trials (RCTs), eight for falls (n = 2426) and 12 for non-vertebral fractures (n = 42,279), there was a significant dose-response relationship between higher-dose and higher achieved 25(OH)D and greater fall and fracture prevention. Optimal benefits were observed at the highest dose tested to date for 700 to 1000 IU vitamin D per day or mean 25(OH)D between 75 and 110 nmol/l (30-44 ng/ml). Prospective cohort data on cardiovascular health and colorectal cancer prevention suggested increased benefits with the highest categories of 25(OH)D evaluated (median between 75 and 110 nmol/l). In 25 RCTs, mean serum calcium levels were not related to oral vitamin D up to 100,000 IU per day or achieved 25(OH)D up to 643 nmol/l. Mean levels of 75 to 110 nmol/l were reached in most RCTs with 1,800 to 4,000 IU vitamin D per day without risk.
Our analysis suggests that mean serum 25(OH)D levels of about 75 to 110 nmol/l provide optimal benefits for all investigated endpoints without increasing health risks. These levels can be best obtained with oral doses in the range of 1,800 to 4,000 IU vitamin D per day; further work is needed, including subject and environment factors, to better define the doses that will achieve optimal blood levels in the large majority of the population.
Osteoporosis International 12/2009; 21(7):1121-32. · 4.58 Impact Factor
ABSTRACT: Higher physiologic testosterone levels among community dwelling older men and women may protect against falls, and this benefit may be further increased among those taking additional vitamin D plus calcium.
The aim of this study is to investigate sex hormone levels and fall risk in older men and women.
One hundred and ninety-nine men and 246 women age 65+ living at home were followed for 3 years after baseline assessment of sex hormones. Analyses controlled for several covariates, including baseline 25-hydroxyvitamin D, sex hormone binding globulin, and vitamin D plus calcium treatment (vitD+cal).
Compared to the lowest quartile, men and women in the highest quartile of total testosterone had a decreased odds of falling (men: OR = 0.22; 95% CI [0.07,0.72]/ women: OR = 0.34; 95% CI [0.14,0.83]); if those individuals also took vitD+cal, the fall reduction was enhanced (men: OR = 0.16; 95% CI [0.03,0.90] / women: OR = 0.15; 95% CI [0.04,0.57]). Similarly, women in the top quartile of dihydroepiandrosterone sulfate (DHEA-S) had a lower risk of falling (OR = 0.39; 95% CI [0.16,0.93]). Other sex hormones and SHBG did not predict falling in men or women.
Higher testosterone levels in both genders and higher DHEA-S levels in women predicted a more than 60% lower risk of falling. With vitD+cal, the anti-fall benefit of higher physiologic testosterone levels is enhanced from 78% to 84% among men and from 66% to 85% among women.
Osteoporosis International 04/2008; 19(9):1307-14. · 4.58 Impact Factor