Evaluation of sun holiday, diet habits, origin and other factors as determinants of vitamin D status in Swedish primary health care patients: a cross-sectional study with regression analysis of ethnic Swedish and immigrant women

Abstract

BackgroundDeterminants of vitamin D status measured as 25-OH-vitamin D in blood are exposure to sunlight and intake of vitamin D through food and supplements. It is unclear how large the contributions are from these determinants in Swedish primary care patients, considering the low radiation of UVB in Sweden and the fortification of some foods. Asian and African immigrants in Norway and Denmark have been found to have very low levels, but it is not clear whether the same applies to Swedish patients. The purpose of our study was to identify contributors to vitamin D status in Swedish women attending a primary health care centre at latitude 60°N in Sweden.MethodsIn this cross-sectional, observational study, 61 female patients were consecutively recruited between January and March 2009, irrespective of reason for attending the clinic. The women were interviewed about their sun habits, smoking, education and food intake at a personal appointment and blood samples were drawn for measurements of vitamin D and calcium concentrations.ResultsPlasma concentration of 25-OH-vitamin D below 25 nmol/L was found in 61% (19/31) of immigrant and 7% (2/30) of native women. Multivariate analysis showed that reported sun holiday of one week during the last year at latitude below 40°N with the purpose of sun-bathing and native origin, were significantly, independently and positively associated with 25-OH-vitamin D concentrations in plasma with the strongest association for sun holiday during the past year.ConclusionsVitamin D deficiency was common among the women in the present study, with sun holiday and origin as main determinants of 25-OH-vitamin D concentrations in plasma. Given a negative effect on health this would imply needs for vitamin D treatment particularly in women with immigrant background who have moved from lower to higher latitudes.

Vitamin D treatment in Somali women living in Sweden – Two randomized, placebo‐controlled studies

“…The data are in concordance with results from other studies, where the recommended exposure to sunlight of nonwestern immigrants failed to increase the S‐25(OH)D levels up to the sufficient level (>50 nmol/l) . Sunny holidays of 1 week at latitudes below 40°N, for the purpose of sunbathing, were positively associated with S‐25(OH)D levels in immigrant women living in Sweden . Vitamin D supplementation appears to be necessary to achieve optimum S‐25(OH)D concentrations in nonwestern immigrants …”

“…29 Sunny holidays of 1 week at latitudes below 40°N, for the purpose of sunbathing, were positively associated with S-25(OH)D levels in immigrant women living in Sweden. 30 Vitamin D supplementation appears to be necessary to achieve optimum S-25 (OH)D concentrations in nonwestern immigrants. 29 There are a limited number of placebo-controlled studies in immigrants or patients at high risk of vitamin D deficiency.…”

Adequate vitamin D levels in a Swedish population living above latitude 63°N: The 2009 Northern Sweden MONICA study

“…In most studies, just as in MONICA, women have slightly higher levels of vitamin D. This may be due to more sunbathing ( 6 ), outdoor activities ( 6 , 7 ), sun holidays ( 9 , 17 ) and a more frequent use of vitamin D supplementation among women ( 9 , 14 ).…”

“…In previous Nordic studies of the domestic population, mean values are generally adequate, the seasonal variation is significant and the prevalence of vitamin D deficiency is low ( 6 – 15 ) However, in specific populations such as immigrants, both insufficiency and deficiency are significantly more common and might affect both health and quality of life ( 16 , 17 ). Direct comparisons of contemporary vitamin D levels in the population across Europe are scarce but a large multicentre study from 2013 reported higher vitamin D levels with higher latitude in Europe ( 18 ).…”

Long-term adherence and effects on grip strength and upper leg performance of prescribed supplemental vitamin D in pregnant and recently pregnant women of Somali and Swedish birth with 25-hydroxyvitamin D deficiency: a before-and-after treatment study

“…Non-adherence to medication and advice can be due to lack of cultural competence from a care-giver perspective leading to that clinical needs are missed [14] such as the deficient levels of vitamin D (25-OHD) in pregnant non-Western women living in Europe [15–17], in adolescent girls in England [18], and in post-partum mothers [15]. Lack of vitamin D also occurs in high frequency in native populations of women in Beijing [19] and Denmark [20] while Swedish women in general practice seldom have levels below 25 nmol/L [21]. Notably, no clinical data were provided in any of the above mentioned studies.…”