ABSTRACT
OBJECTIVE: The aim was to study whether the seasonal variation of vitamin D [25(OH)-D or calcidiol] is similar or different in younger and older women living in a southern country. METHODS: Measurement of serum 25(OH)-D concentration in 739 Chilean women aged 20 to 87 years, residents of Santiago (latitude: 33.4° South) who, during a routine gynaecological checkup, agreed to be evaluated. RESULTS: The mean serum concentration of 25(OH)-D for the group was 24.1â±â10.5âng/mL. In women 20 to 39 years, the mean was significantly different from the mean of the ≥60 years old group (25.8â±â10.6âng/mL vs 23.9â±â11.1âng/mL; Pâ<â0.02). Globally, 38.4% of participants had vitamin D deficiency and 36.1% insufficiency. A deficiency was present in 28.4% of the 20 to 39 years old, and in 43.9% in the ≥60 years old group (Pâ<â0.004). In the whole group, a lower proportion (Pâ<â0.0001) of vitamin D deficiency cases in the youngest women occurred during the summer (23.7%) in comparison to the winter (47.7%). It was observed that the proportion of participants in the 20 to 39 years old group with vitamin D deficiency fell from 48.9% in winter to 4.9% in summer (Pâ=â0.0001). In the older groups, this change (less deficiency) is progressively smaller, 51.2% to 27.6% (Pâ=â0.0020) in women 40 to 59 years old, and it does not happen in women ≥60 years (40% with vitamin D deficiency). CONCLUSIONS: Serum vitamin D deficiency [25(OH)-D or calcidiol] is highly prevalent in Santiago, especially in older women (≥60 y) throughout the year. In contrast, in younger women (<40 y), the vitamin D deficiency tends to disappear during summer. More epidemiological studies and targeted prevention actions on vitamin D deficiency are warranted.
