“…Consistent predictors across these studies for lower values were age, albeit with differing findings, some studies showing older age to be a risk factor, 57 , 67 , 69 while others point to younger age, 41 , 42 , 77 female gender in adults 41 , 61 , 63 , 72 , 75 , 82 and children, 83 - 89 winter season, sunlight exposure and veiling, 40 , 41 , 44 , 56 , 60 , 63 , 66 , 75 , 78 , 81 , 90 , 92 except in some studies from gulf countries where summer registers lowest values in studies from the United Arab Emirates, 75 , 77 pollution, 43 low calcium or vitamin D dietary intake, 67 , 77 , 80 , 81 , 90 , 92 and exclusive breast feeding in infants 88 . Other predictors included high BMI and /or increased adiposity, 39 , 60 , 66 - 68 , 72 , 93 and lower SES status or educational level 44 , 60 , 64 , 68 , 80 , 83 .The impact of menopause was not consistent across studies, whereas premenopausal women had higher levels in the study from Saudi Arabia, 67 the opposite was found in UAE 77 Table 1. details studies conducted in adults, Table 2 in children, Table 3 in mothers-neonates, by country, and highlights are underscored here-in.…”