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Background Dietary sources of vitamin D (both natural and fortified) are increasingly contributing to consumers' vitamin D intake and status. Therefore, the present study aimed to validate a vitamin D food frequency questionnaire (FFQ) for the assessment of habitual vitamin D intake. Methods A total of 49 apparently healthy consenting adults (aged 18-64 years) from the local community were sampled at the end of winter. Dietary intakes were recorded using a 4-day weighed food record (4d-WFR) and a 17-item FFQ based on foods known to contribute to dietary vitamin D intake. Fasting vitamin D status was quantified by serum 25-hydroxyvitamin D [25(OH)D] using liquid chromatography tandem mass spectrometry. The method of triads was applied using these three measurements to determine the overall validity of the FFQ. Results Vitamin D intakes from 4d-WFR ranged between 0.42 and 31.65 μg day(-1), whereas intakes determined from the FFQ ranged from 1.03 to 36.08 μg day(-1). Serum 25(OH)D concentrations ranged between 12.89 and 279.00 nmol L(-1). The mean (SD) difference between the FFQ and 4d-WFR was +1.62 ( 3.86). There were strong correlations between the vitamin D intake estimated by the FFQ and that from the 4d-WFR (r = 0.562) and also with serum 25(OH)D concentrations (r = 0.567). Vitamin D intake estimated from the 4d-WFR was also strongly correlated with serum 25(OH)D concentrations (r = 0.411). The overall validity coefficient calculated using the method of triads was high (0.881). Conclusions The vitamin D FFQ has been validated for use in future studies aiming to assess habitual vitamin D intake.

Background Studies investigating obesity and cardiometabolic risk have focused on ‘at-risk’ populations and methodological inconsistencies have produced equivocal findings. The present cross-sectional study investigated indices of body composition as predictors of cardiometabolic risk and their relationship with inflammation in apparently healthy young adults. Methods A fasting blood sample was taken from consenting adults (160 males, 32 females, aged 18–40 years) for assessment of cardiometabolic risk markers (blood pressure, lipid profiles and insulin resistance) and inflammatory markers (C-reactive protein, tumour necrosis factor-α, interleukin-6, interleukin-10 and adiponectin). Together with anthropometry, fat mass (FM) and fat-free mass (FFM) were determined by dual-energy X-ray absorptiometry. FM was expressed in absolute terms (kg), as well as relative to total body weight (%), height [FM index (FMI, kg m−2)] and FFM (FM : FFM,%). Results Although anthropometric indices were associated with most cardiometabolic risk markers, the strongest relationship was observed with FMI. Relative to having a low cardiometabolic risk (≤2 markers above clinically relevant cut-offs), each kg m−2 increase in FMI, increased the likelihood of having an increased cardiometabolic risk by 29% (odds ratio = 1.29; 95% confidence interval = 1.12–1.49). Inflammatory markers were not associated with body composition or cardiometabolic risk. Conclusions FMI was the strongest predictor of overall cardiometabolic risk but not inflammation per se. However, anthropometric indices, such as body mass index and waist-to-height ratio, remain valuable surrogate measures of adiposity in this group, particularly when risk markers are considered independently.