Serum 25-hydroxyvitamin D level, chronic diseases and all-cause mortality in a population-based prospective cohort: the HUNT Study, Norway

Abstract

ObjectiveTo investigate the association of vitamin D status with all-cause mortality in a Norwegian population and the potential influences of existing chronic diseases on the association.DesignA population-based prospective cohort study.SettingNord-Trøndelag County, Norway.ParticipantsA random sample (n=6613) of adults aged 20 years or older in a cohort.MethodsSerum 25-hydroxyvitamin D (25(OH)D) levels were measured in blood samples collected at baseline (n=6377). Mortality was ascertained from the Norwegian National Registry. Cox regression models were applied to estimate the HRs with 95% CIs for all-cause mortality in association with serum 25(OH)D levels after adjustment for a wide spectrum of confounding factors as well as chronic diseases at baseline.ResultsThe median follow-up time was 18.5 years, during which 1539 subjects died. The HRs for all-cause mortality associated with the first quartile level of 25(OH)D (<34.5 nmol/L) as compared with the fourth quartile (≥58.1 nmol/L) before and after adjustment for chronic diseases at baseline were 1.30 (95% CI 1.11 to 1.51) and 1.27 (95% CI 1.09 to 1.48), respectively. In the subjects without chronic diseases at baseline and with further exclusion of the first 3 years of follow-up, the corresponding adjusted HR was 1.34 (95% CI 1.09 to 1.66).ConclusionsLow serum 25(OH)D level was associated with increased all-cause mortality in a general Norwegian population. The association was not notably influenced by existing chronic diseases.

Is there an association between vitamin D status and risk of chronic low back pain? A nested case–control analysis in the Nord-Trøndelag Health Study

“… 37 38 In data with measurements from the HUNT2 survey, low 25(OH)D levels showed a clear association with all-cause mortality in a prospective study with a median follow-up time of 18.5 years. 39 Thus potential relationships between 25(OH)D levels and disease should still persist in a study such as the current one with 11 years of follow-up, although associations may be attenuated. The state of relevant confounders may also change during a long follow-up.…”

Serum 25-hydroxyvitamin D level in relation to weight change and the risk of weight gain in adults of normal weight at baseline: the Norwegian HUNT cohort study

“…Categorisation of physical activity in the HUNT study has been described in detail previously. 23 Total sitting time was used as a marker for sedentary lifestyle and was categorised as <4, 5-7 and ≥8 hours/day. Chronic illness was a variable generated from responses to several questions on major somatic diseases (Have you had or do you have any of the following diseases: myocardial infarction (heart attack)/angina pectoris (chest pain)/stroke (brain haemorrhage)/diabetes/cancer?…”

Vitamin D deficiency and infection risk in kidney transplant recipients: A single‐center cohort study

“…In addition to its well‐established role in regulating mineral balance and bone metabolism, vitamin D exerts a far larger number of “non‐classical” biological functions in extraskeletal tissues . Vitamin D deficiency has been accordingly associated with all‐cause and cardiovascular‐specific mortality in the general population, patients with end‐stage renal disease (ESRD), or KT recipients …”

“…In addition to its well-established role in regulating mineral balance and bone metabolism, vitamin D exerts a far larger number of "non-classical" biological functions in extraskeletal tissues. [1][2][3][4][5] Vitamin D deficiency has been accordingly associated with all-cause and cardiovascular-specific mortality in the general population, 6,7 patients with end-stage renal disease (ESRD), 8,9 or KT recipients. 10 Since the first observations linking sunlight exposure and tuberculosis susceptibility, 11 the immunomodulatory roles displayed by vitamin D have been extensively demonstrated.…”