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

Abstract

BackgroundEven though vitamin D is mainly produced by exposure to sunlight, little is known regarding vitamin D levels in populations living in sub-Arctic areas with little or no daylight during winter.ObjectiveWe describe distributions of vitamin D3 and the prevalence of adequate levels in a population living above 63°N.DesignWe sampled 1,622 randomly selected subjects, aged 25–74 years, between January and May, 2009, as part of the Northern Sweden MONICA study (69.2% participation rate). By using HPLC, 25(OH) vitamin D3 was analysed. Levels used for definitions were deficient, D3<25 nmol/l (<10 ng/ml); insufficient, D3 25–49.9 nmol/l (10–20 ng/ml); and adequate, D3≥50 nmol/l (20 ng/ml).ResultsMean (median) level of vitamin D3 was 65.2 (63.6) nmol/l in men and 71.0 (67.7) nmol/l in women. Adequate levels were found in 79.2%, more often in women (82.7%) than in men (75.6%). Only 0.7% of the population were vitamin D3–deficient but 23.1% of men and 17.1% of women had insufficient levels. Levels of vitamin D3 increased with age and insufficient status was most common among those aged 25–34 years, 41.0% in men and 22.3% in women.If subjects using vitamin D-supplementation are excluded, the population level of D3 is 1–2 nmol/l lower than in the general population across sex- and age groups. There were no differences between the northern or the southern parts, between urban or rural living or according to educational attainment. Those subjects born outside of Sweden or Finland had lower levels.ConclusionThe large majority living close to the Arctic Circle in Sweden have adequate D3 levels even during the second half of the dark winter. Subjects with D3 deficiency were uncommon but insufficient levels were often found among young men.

Longitudinal associations between lifestyle and vitamin D: A general population study with repeated vitamin D measurements

“…Thus, improvement in diet, decreased BMI, increased physical activity, quitting smoking, and increased alcohol consumption were independently associated with an increased 25-OH-D during a 5-year period. Except for the association between changes in intake of alcohol, dietary and smoking habits, and vitamin D status, these findings were supported by additional analyses In line with previous studies, vitamin D status was generally higher in women than men [26,27].…”

Vitamin D is not associated with incident dementia or cognitive impairment: an 18-y follow-up study in community-living old men

“…The limitations of the study include the lack of repeated measurements of plasma 25(OH)D and dietary vitamin D intakes, the lack of information on sun exposure as a covariate, and the inclusion of men only. In this overall healthy cohort, there were very few participants with low concentrations of 25(OH)D; however, this factor is in line with previous studies in community-dwelling people (58,59) in Sweden. Future studies may want to focus on a population in whom vitamin D deficiency is more prevalent.…”

The impact of seasonal variation of 25-hydroxyvitamin D and parathyroid hormone on calcium levels

“…The present study confirmed previous results from studies of the seasonal variation of vitamin D in Scandinavia [9][10][11] as we found 42% higher 25(OH)D level in summer compared to winter. Even the PTH level showed a difference between summer and winter with 7% lower PTH level in summer compared to winter, also in accordance with previous reports [1].…”