Vitamin D synthesis in the skin through sun exposure is a significant source of vitamin D. Limited sun exposure due to lifestyle factors, geographic location, or excessive use of sunscreen can contribute to deficiency that supplements alone may not fully address.
Genetic factors can influence how a child's body processes vitamin D. Some children may have genetic polymorphisms that affect the metabolism of vitamin D, making it harder to reach sufficient levels even with supplements.
Chronic health conditions or medications that affect the liver or kidneys can interfere with the conversion of vitamin D into its active form, 1,25-dihydroxyvitamin D, reducing the effectiveness of supplementation.
Sedentary lifestyles and indoor activities reduce exposure to natural sunlight. Environmental factors such as pollution can also block UVB rays necessary for vitamin D synthesis in the skin.