An Integrated Predictive Model of Population Serum 25(OH)D for Application in Strategy Development for Vitamin D Deficiency Prevention

To enable strategies for increased dietary supply of vitamin D, such as through fortification approaches, be evidence‐based, there is a need to develop models of usual food consumption, vitamin D intakes and serum 25(OH)D concentrations. The objective of this work was to develop an integrated mathematical model, using data on ultraviolet (UV) B availability, exposure and dietary intake, to predict serum 25(OH)D concentrations in a nationally representative sample of adults. Data on UVB availability and hours of sunlight in Ireland were used in a mathematical model (1) to predict serum 25(OH)D in Irlsh adults, aged 18‐64 y. A regression equation from our dose‐related vitamin D RCT in adults (2) was intregrated into the model which allowed us to predict the impact of changes in dietary vitamin D to the contribution to serum 25(OH)D concentration within the population. For illustrative purposes, the impact of substituting biofortified eggs (see red line, Figure) for usual eggs (blue line) was modelled in our national adult nutrition survey and the resulting hypothetical increase in median vitamin D intake (1.26 μg/d) was utilized in the model.The model predicted that the population % vitamin D deficiency (<30 nmol/L) in an extended winter‐period was 18.1% (versus 18.6% measured), and which was reduced to 15.8% with inclusion of biofortified eggs in adult population diet, despite that only 47% are egg consumers. In conclusion, mathematical models have the ability to inform how vitamin D food fortification in various constructs may impact on the population serum 25(OH)D concentrations and prevalence of vitamin D deficiency