Vitamin D levels in an Australian population

Area of Science:

• Public Health
• Endocrinology
• Nutritional Science

Background:

• Vitamin D levels are a growing public health concern.
• Limited studies in Australia have assessed general population vitamin D status.
• This study addresses the need for population-level data in South Australia.

Purpose of the Study:

• To measure serum 25-hydroxy vitamin D (25(OH)D) levels in a large South Australian cohort.
• To investigate associations between 25(OH)D levels and demographic factors, seasons, and health risks.
• To identify factors contributing to vitamin D deficiency in the general population.

Main Methods:

• A longitudinal cohort study of 2413 participants in Adelaide, South Australia (2008-2010).
• Serum 25(OH)D levels were analyzed in relation to age, sex, income, education, country of birth, season, supplement use, physical activity, BMI, and smoking status.
• Statistical analyses examined unadjusted and adjusted mean levels and prevalence of vitamin D deficiency (levels <50 and <75 nmol/L).

Main Results:

• The overall mean serum 25(OH)D level was 69.2 nmol/L, with 22.7% of participants deficient (<50 nmol/L).
• Higher 25(OH)D levels were observed in males, during summer and autumn, and in non-obese individuals.
• Lower levels were associated with smoking and insufficient physical activity (<150 min/week).

Conclusions:

• Vitamin D deficiency is a significant issue in South Australia, impacting nearly 25% of the population.
• Factors such as obesity, season, and physical activity levels are independently associated with vitamin D status.
• There is a clear need for improved public health strategies to address widespread vitamin D deficiency.