Validation of a Vitamin D Specific Questionnaire to Determine Vitamin D Status in Athletes

Abstract

The study objective was to validate a food frequency and lifestyle questionnaire (FFLQ) to assess vitamin D intake and lifestyle factors affecting status. Methods: Data collected previously during the fall (n = 86), winter (n = 49), and spring (n = 67) in collegiate-athletes (Study 1) and in active adults (n = 123) (Study 2) were utilized. Study 1: Vitamin D intake and ultraviolet B exposure were estimated using the FFLQ and compared to serum 25(OH)D concentrations via simple correlation and linear regression modeling. Study 2: Vitamin D intake from food was estimated using FFLQ and compared to vitamin D intake reported in 7-Day food diaries via paired t-test and Bland–Altman analysis. Results: Study 1: Serum 25(OH)D was not associated with vitamin D intake from food, food plus supplements, or sun exposure, but was associated with tanning bed use (r = 0.39) in spring, supplement use in fall (r = 0.28), and BMI (body mass index) (r = −0.32 to −0.47) across all seasons. Serum 25(OH)D concentrations were explained by BMI, tanning bed use, and sun exposure in fall, (R = 0.42), BMI in winter (R = 0.32), and BMI and tanning bed use in spring (R = 0.52). Study 2: Estimated Vitamin D intake from food was 186.4 ± 125.7 via FFLQ and 148.5 ± 228.2 IU/day via food diary. There was no association between intake estimated by the two methodologies (r = 0.12, p < 0.05). Conclusions: FFLQ-estimated vitamin D intake was not associated with serum 25(OH)D concentration or food-record-estimated vitamin D intake. Results highlight the difficulty of designing/utilizing intake methodologies for vitamin D, as its status is influenced by body size and both endogenous and exogenous (dietary) sources.

Dietary Macronutrient and Micronutrient Intake over a 7-Day Period in Female Varsity Ice Hockey Players

“…It has been shown that male and female athletes that train indoors during the fall and winter months suffer from low vitamin D levels [ 40 ]. Since vitamin D is only found in limited natural and fortified foods such as fatty fish, mushrooms, egg yolks, and cereals, it is unlikely that adequate vitamin D status can be maintained through food alone in the present athlete population [ 41 ].…”

Vitamin D Synthesis Following a Single Bout of Sun Exposure in Older and Younger Men and Women

“…Body mass index (BMI) was calculated as weight divided by height in meters squared and body surface area (BSA) was calculated using the Mosteller equation [ 36 ]. Participants also completed a vitamin D-specific food frequency and lifestyle questionnaire (FFLQ) [ 37 ]. The FFLQ addresses questions about the frequency of consumption of vitamin D-containing foods, vitamin D supplementation, sun exposure and tanning bed usage.…”

Vitamin D Sources, Metabolism, and Deficiency: Available Compounds and Guidelines for Its Treatment

“…Conversely, researchers observed a significant association of serum 25(OH)D with tanning bed use in the spring, supplement use in the fall, and BMI across all seasons. These results indicate the influence of factors—other than diet—on the serum concentrations of calcifediol [ 33 ]. Because the main dietary sources of vitamin D are of animal origin, a recent simulation study estimated the dietary shifts necessary to optimize vitamin D intake and minimize the carbon footprint.…”