View clinical trials related to Vitamin D Status.
Filter by:Vitamin D deficiency is associated with a heightened risk for developing type 2 diabetes, hypertension, and osteopenia/osteoporosis. Vitamin D is made in the skin when it is exposed to sunlight and it is also obtained from the diet and dietary supplements. Older people, individuals with high skin pigmentation, obese and sedentary individuals have low levels of Vitamin D because pigmentation blocks Vitamin D production in the skin, aging and physical inactivity are associated with reduced exposure to sunlight, and obesity is associated with the storage of Vitamin D in fat preventing its utilization by muscle, bone and other tissues that require its metabolic action. These conditions are also associated with heightened risk for developing type 2 diabetes, glucose intolerance, hypertension, and osteopenia/osteoporosis in older and obese individuals. This is particularly heightened in older women who tend to have increased body fat, are more physically inactive and are at high risk for central obesity and its metabolic consequences of diabetes, hypertension and osteoporosis.
The study is a randomized, controlled, double blinded study evaluating the effect of recommended (400 IU) and 1 200 IU daily vitamin D substitution, given from 2 weeks to 2 years of age, on growth, bone development, neurologic and cognitive development, frequence of infectious diseases, allergic symptoms, and development of immunoregulation assessed at 2 years of age.
Infertility is a common and psychologically devastating problem for 20% of Canadian couples. Approximately, 20% of infertile couples are diagnosed with unexplained infertility and left without an explanation for their inability to have a baby. Pathological uterine receptivity and embryo implantation are hypothesized mechanisms underlying sub-fertility in these couples. Embryo implantation requires a complicated sequence of events involving the differentiation of endometrial cells to attain uterine receptivity and the synchronized interaction between maternal and embryonic tissues. Vitamin D has been hypothesized to play a role in this poorly understood process. Vitamin D is a known regulator of signal transduction pathways involved in embryo implantation and its receptors are involved in calcium-regulation in various reproductive tissues including, the ovary, uterus, and placenta. In Canada, the prevalence of Vitamin D insufficiency is approximately 34-50%. The goal of the proposed study is to determine the prevalence of vitamin D insufficiency in an infertile population and whether this prevalence is higher than in average Canadian reproductive age women. More importantly, we will investigate whether vitamin D insufficiency in our infertile population translates to impaired implantation and reduced clinical pregnancy rates. Insight into vitamin D's role in reproduction is essential not only to provide scientific understanding of the mechanism underlying embryo implantation, but also because vitamin D supplementation could provide an easy and safe means of treating infertility.
The purpose of the study is to determine the frequency of UVB radiations necessary to maintain the Vitamin D level during winter time.
The purpose of the study is to determine the importance of the UV intensity and the UVB dose on the Vitamin D response after UVB.
The purpose of this study is to investigate the relation between vitamin D production after UVB and exposed body surface areas with different UVB doses.
This study is conducted in two phases. At the first phase, the prevalence of vitamin D insufficiency in primary school-children in Tehran is determined during the cold seasons of 2008. Then, the efficacy of calcium-vitamin D-fortified milk, -orange juice and supplement is compared in six selected primary schools.
Patients need vitamin D which is normally produced in the skin in response to ultraviolet light from the sun. Vitamin D is important for calcium absorption and good bone health. Physicians have been using sunscreens to protect patients from skin cancer and the aging effects of sunlight for a least a half a century. Dermatologists have promoted sunscreen use to restrict sunlight exposure especially in white Caucasians. If this behavior is done 100% of the time when outdoors individuals may suffer from vitamin D deficiency. It is impossible to influence persons' behavior to wear sunscreens all the time when outdoors. With the use of sunless tanning agent (DHA), once a week, we can obtain a continuous sunscreen in the top layer of the skin that will not wash off, can't be removed with soap and water, or removed by perspiration. Under these circumstances we can answer the scientific question, will sunscreen use inhibit the production of vitamin D in the skin?
We have just completed a randomized, clinical trial of 100,000 IU Vitamin D3 given as a single dose at the beginning of winter. We found a wide range of responses to the dose. This study proposes that genetic differences account for some of the variation in response of 25(OH)D levels after treatment with oral Vitamin D.