Limited Sunlight Exposure: Insufficient exposure to sunlight, especially in individuals who live in northern latitudes or spend most of their time indoors.
Seasonal Changes: Limited sunlight during certain seasons, such as winter, can decrease the production of vitamin D, increasing the likelihood of deficiency.
Aging: The skin's ability to produce vitamin D decreases as we age, making older adults more prone to deficiency.
Obesity: Excess body fat can sequester vitamin D, making it less available for use in the body, leading to lower levels of vitamin D in obese individuals.
Limited Dietary Intake: A diet low in vitamin D-rich foods, such as fatty fish and fortified products, or a vegan/vegetarian diet that excludes animal-based products.
Malabsorption Issues: Gastrointestinal conditions like celiac disease, Crohn's disease, and inflammatory bowel disease can interfere with the absorption of vitamin D from the diet.
Kidney or Liver Disease: Kidney or liver disorders can impair the conversion of vitamin D into its active form or affect its transport, resulting in vitamin D deficiency.
Medications: Some medications, such as certain anticonvulsants, glucocorticoids, and antiretrovirals, can interfere with vitamin D metabolism.
Genetic Factors: Certain genetic variations can affect the metabolism and transport of vitamin D, increasing the risk of deficiency.