Tracking of Serum 25-Hydroxyvitamin D Levels During 14 Years in a Population-based Study and During 12 Months in an Intervention Study

Abstract

Low serum 25-hydroxyvitamin D (25(OH)D) levels are associated with risk factors for cardiovascular disease, and they also appear to predict later development of type 2 diabetes, cancer, and an increased mortality rate. These predictions are all based on a single 25(OH)D measurement, but so far there are no known reports on tracking of serum 25(OH)D levels. In the present Norwegian study, serum 25(OH)D levels were measured 1) in 2,668 subjects in the 1994 and 2008 Tromsø surveys and 2) every third month for 1 year in 94 subjects randomly assigned to placebo in a vitamin D intervention study. There was a marked seasonal variation in 25(OH)D, and, depending on the method of adjusting for season, the correlation coefficient between serum 25(OH)D measurements from 1994 and 2008 ranged from 0.42 to 0.52. In the 1-year intervention study, the correlation between baseline and 12-month values was 0.80. Apart from the effect of season, changes in weight, intake of vitamin D, and physical activity were related to change in serum 25(OH)D levels. Tracking of serum 25(OH)D appears similar to that for blood pressure and serum lipids, and it provides some support for the use of a single 25(OH)D measurement to predict future health outcomes.

Plasma 25‐hydroxyvitamin D and the risk of breast cancer in the European prospective investigation into cancer and nutrition: A nested case–control study

“…Although repeated measurements are desirable, several cohort studies have shown that 25(OH)D levels remain relatively stable over time. [46][47][48] Lastly, recent study results suggest that levels of the vitamin D-binding protein may affect associations between 25(OH)D and cancer risk. 49,50 Thus, another limitation of our study is that circulating levels of the vitamin D-binding protein were not assayed.…”

Vitamin D3 increases in abdominal subcutaneous fat tissue after supplementation with vitamin D3

“…In Northern Norway at 708 latitude, there is no effective UVB radiation and no cutaneous vitamin D synthesis from October till March (2), and the daily average intake of vitamin D is only 300 IU (3,4). Given that 25-hydroxyvitamin D 3 (25(OH)D 3 ), the metabolite used to evaluate a subject's vitamin D status, has a half-life of 10-40 days (5), one would expect the serum 25(OH)D 3 levels by the end of the UVB winter to be very low. However, data from Tromsø show only a 25% decline during this period (6).…”

Can Vitamin D Slow Progression of Osteoarthritis?

“…In the few studies that prospectively examined predictors of change in 25(OH)D, predictors included measures of body size [21,22], physical activity [21], vitamin D intake and exogenous estrogen dose [23]. Studies suggest that vitamin D may have implication on the radiographic manifestations of OA [24,25] or cartilage loss in knee joint [26].…”