Prevalence of vitamin D deficiency and insufficiency among schoolchildren in Greece: the role of sex, degree of urbanisation and seasonality

Abstract

The current study was aiming to report the prevalence of suboptimal vitamin D status among schoolchildren in Greece and investigate the role of sex, urbanisation and seasonality on vitamin D status. A sample of 2386 schoolchildren (9-13 years old) from four distinct prefectures was examined. The prevalence of 25-hydroxyvitamin D (25(OH)D) concentration <30 and <50 nmol/l (vitamin D deficiency and insufficiency respectively) was 5·2 and 52·5 %, respectively. Girls had a higher prevalence of 25(OH)D<30 (7·2 v. 3·2 %) and 50 nmol/l (57·0 v. 48·0 %) than boys (P<0·001). The highest prevalence rates of 25(OH)D<30 and 50 nmol/l (9·1 and 73·1 %, respectively) were observed during spring (April to June), whereas the lowest (1·5 and 31·9 %, respectively) during autumn (October to December). The prevalence of 25(OH)D<50 nmol/l was higher in urban/semi-urban than rural regions, particularly during spring months (74·6 v. 47·2 %; P<0·001). Female sex, urban/semi-urban region of residence and spring months were found to increase the likelihood of vitamin D deficiency and insufficiency, with the highest OR observed for spring months (7·47; 95 % CI 3·23, 17·3 and 5·14; 95 % CI 3·84, 6·89 for 25(OH)D<30 and 50 nmol/l respectively). In conclusion, despite the southerly latitude, the prevalence of low vitamin D status among primary schoolchildren in Greece is comparable to or exceeds the prevalence reported among children and adolescents on a European level. Sub-populations at highest risk are girls in urban/semi-urban areas during spring months, thus indicating the need for effective initiatives to support adequate vitamin D status in these population groups.

Effect of the month of birth on the height of young adult males

“…Authors have suggested different hypotheses such as the light‐dependent activity of the pineal gland and melatonin production (Weber et al, ), or seasonal differences in morbidity due to infectious diseases in tropical countries (Sohn, ). It is also worthy of note that in a recent study of the prevalence of vitamin D deficiency in Greece (Manios et al, ), the periods of the highest and lowest prevalence of hypovitaminosis D were essentially the same with the respective periods of lower and peak height observed in our study. This observation may lead to another hypothesis, namely, that either vitamin D is an important contributor of the early postnatal growth, as some authors have suggested (Roth, Perumal, Al Mahmud, & Baqui, ), or that both parameters are independently affected by the same condition, that is, solar radiation.…”

The Prevalence of Vitamin D Deficiency Among Children of 1 - 6 Years Old, Tehran, Iran

“…Also, Mainos et al attributed most of the vitamin D deficiency prevalence in girls of 9 -13 years old in a city in Greece to an increase in indoor activities. Besides, some studies have attributed lower prevalence of vitamin D deficiency in men, despite having an equal BMI with women, to 10% -15% less body fat content, which leads to less amount of vitamin D stored in body fat and more amount of vitamin D available in blood (2,34,35).…”

Vitamin D insufficiency is associated with insulin resistance independently of obesity in primary schoolchildren. The healthy growth study

“…The VDSP protocol for standardization of serum 25(OH)D values was applied to serum 25(OH)D data arising from previously analyzed serum samples using the chemiluminescence immunoassay analysis. The VDSP protocol and its application has been outlined in detail elsewhere, while more analytical information on the procedures followed for the standardization of serum 25(OH)D values in the present study has been recently provided elsewhere …”