Vitamin D status among adults in Germany – results from the German Health Interview and Examination Survey for Adults (DEGS1)

Abstract

BackgroundIn 1998, more than half of the adult population in Germany had serum 25-hydroxy-vitamin-D [25(OH)D] levels below the common threshold of 50 nmol/l. Since then, there has been a lot of attention for vitamin D in the scientific community, the media and the general population and serum 25(OH)D levels may have increased as a consequence. With data from the ‘German Health Interview and Examination Survey for Adults’ (DEGS1) the current situation of vitamin D status can be analysed.MethodsDEGS1, a national health survey among adults in Germany conducted by the Robert Koch Institute between 2008 and 2011, included 6,995 persons with available serum 25(OH)D levels. We calculated the proportion of participants with serum 25(OH)D levels <30 nmol/l, 30- < 50 nmol/l and > =50 nmol/l overall and according to age, season and latitude of residence as well as percentiles of serum 25(OH)D according to month of examination. Determinants of vitamin D status were analysed with multiple linear regression models.ResultsMean serum 25(OH)D level was 45.6 nmol/l with no significant sex differences (p = 0.47). 61.6 % of the participants had serum 25(OH)D levels <50 nmol/l, 30.2 % had levels <30 nmol/l. During summer, half of the participants had levels > =50 nmol/l, during winter time, 25 % of the participants had levels <30 nmol/l. A significant latitudinal gradient was observed in autumn for men and in winter for women.In multiple linear regression analyses, examination during winter time, residing in northern latitude, non-use of vitamin D supplements, low sport activity, high Body Mass Index (BMI) and high media consumption were independently and significantly associated with lower serum 25(OH)D levels in both sexes. In addition, among women, significant associations with lower 25(OH)D levels were observed for older age and lower socio-economic status, among men, for low vitamin D intake and more residential traffic.ConclusionsSerum 25(OH)D levels below the threshold of 50 nmol/l are still common among adults in Germany, especially during winter and spring and in higher latitudes. Potentially modifiable factors of poorer vitamin D status are higher BMI, lack of sport activity and high media use.

Association between vitamin D and depressive symptoms varies by season: Results from the German Health Interview and Examination Survey for Adults (DEGS1)

“…Full details on analyses have been described elsewhere (Rabenberg et al, 2015). When measured serum 25(OH)D values were below 10 nmol/l, the lower detection level of the assay, values were set to 9 nmol/l.…”

“…The design and methods of DEGS1 have been described in detail elsewhere (Kamtsiuris et al, 2013;Rabenberg et al, 2015;Scheidt-Nave et al, 2012). Briefly, participants were selected using a two-stage stratified random sampling procedure from local population registries at 180 selected sample points across Germany.…”

“…Extended season was defined by the month of examination and categorised as summertime (May-October) in which UVB exposure is more likely to be adequate for vitamin D skin synthesis and wintertime (November-April) (Rabenberg et al, 2015).…”

“…Besides psychosocial factors, different biological and environmental factors are considered to play a potential role in its pathophysiology (Saveanu and Nemeroff, 2012). Increasingly, vitamin D deficiency is being suggested as a contributor to depression (Ju et al, 2013;Milaneschi et al, 2014).…”

“…In this study, we examined the association between 25(OH)D serum levels and current depressive symptoms by season in a nationally representative sample of adults in Germany; a northern European country with well-defined seasons and a latitudinal position between 47°-55°N where vitamin D skin sythesis is limited between October and March (Rabenberg et al, 2015) .…”