Vitamin D status in an Australian patient population: a large retrospective case series focusing on factors associated with variations in serum 25(OH)D

Abstract

ObjectivesTo investigate whether sex, age, medical specialty and seasonal variations in serum concentration of 25-hydroxy vitamin D (25(OH)D) are evident among an Australian patient population.DesignRetrospective study analysing the results of serum 25(OH)D lab tests and vitamin D supplementation from Royal Melbourne Hospital (RMH) between 2014 and 2017.SettingTertiary healthcare centre in Victoria, Australia.Participants30 023 patients (inpatient and outpatient) who had their serum 25(OH)D levels measured at RMH between 2014 and 2017.Main outcome measuresSerum 25(OH)D levels stratified according to patients’ sex, age and medical specialty admitted to, as well as the season and year (2014 to 2017) 25(OH)D level was measured.ResultsMean serum 25(OH)D level of study population was 69.9 nmol/L (95% CI 69.5 to 70.2). Only 40.2% patients in this cohort were sufficient in vitamin D (>75 nmol/L). On average, 25(OH)D levels in male patients were 6.1 units (95% CI 5.4 to 6.9) lower than in females. Linear regression analysis found that 25(OH)D levels increased by 0.16 unit (95% CI 0.14 to 0.18) for every year increase in age. One-way analysis of variance showed patients from neurology had the highest average 25(OH)D level, 76.8 nmol/L (95% CI 74.2 to 79.3) compared with other medical specialties. Mean 25(OH)D level during winter, 64.9 nmol/L (95% CI 64.2 to 65.6) was significantly lower compared with other seasons despite supplementation. Average 25(OH)D level measured in 2014, 71.5 nmol/L (95 CI% 70.8 to 72.2) was significantly higher than levels measured in 2016–2017.ConclusionsThere is a sex, age, medical specialty, seasonal and yearly variation in vitamin D status in an Australian patient population. The association between low vitamin D status and winter despite supplementation suggests other interventions are required to boost serum 25(OH)D levels.

Vitamin D status in active duty Navy military personnel: a systematic review

“…Other important determinants of serum 25(OH)D levels are season and latitude. Seasonal variation in serum 25(OH)D concentration has been confirmed previously, but not all studies included this type of information 36. Included studies were developed at latitudes above ~30°N, which may impact negatively on the SM serum 25(OH)D levels because sunlight is not strong enough to trigger synthesis of vitamin D in the skin at latitudes above ~40°N from October to March 37.…”

“…Seasonal variation in serum 25(OH)D concentration has been confirmed previously, but not all studies included this type of information. 36 Included studies were developed at latitudes above ~30°N, which may impact negatively on the SM serum 25(OH)D levels because sunlight is not strong enough to trigger synthesis of vitamin D in the skin at latitudes above ~40°N from October to March. 37 In fact, Fallowfield et al reported a threefold increase between pre-eployment (home base, UK; 51°N) and mid-deployment (Helmand Province, Afghanistan; 31°N) serum 25(OH)D concentrations in a group of 98 volunteers including Marines deployed from March to June.…”

DeltaF508 CFTR Hetero- and Homozygous Paediatric Patients with Cystic Fibrosis Do Not Differ with Regard to Nutritional Status

“…Discrepancies between our results and the quoted paper may have been caused by geographical location and the associated prevalence of vitamin deficits in the healthy population in these two countries. In Poland, vitamin D3 deficiency of various severities has been found in 90% of healthy adults, children and adolescents [ 21 ]; in Australia, on the other hand, 60% of the population is deficient [ 22 ].…”

The Correlation between Vitamin D Intake and Quality of Life in the 17-35 Age Group

“…8,9,10 The primary source of vitamin D comes from sunlight. 10,11 There are two general forms of vitamin D, namely D-2 (ergocalciferol) and D-3 (cholecalciferol) which can be obtained from foods such as fish oil, eggs, butter, liver, fish such as mackerel, salmon, sardines and tuna. Vitamin D deficiency can be caused by several things, such as decreased intake or absorption of foods containing vitamin D and reduced exposure to sunlight.…”