when effective sun exposure for endogenous vitamin D synthesis is minimal. Mean or median responses of serum 25OHD level to total intake in the winter seasons at northern latitudes (> 49.5°N) and in Antarctica (78°S) (summarized in Table 5-4) were analyzed using a mixed effect model by regression following log transformation with study in a random effects model to control for the large study residual variability for: (1) children and adolescents (boys and girls) ages 6 to 14 years in Finland (Ala-Houhala et al., 1988); (2) young and middle-aged adults ages 19 to 59 years from men in Antarctica (Smith et al., 2009), Ireland (Cashman et al., 2008, 2009), and Finland (Viljakainen et al., 2006, 2009), and Denmark (Schou et al., 2003); and (3) older adult women and men > 60 years of age in Ireland (Cashman et al., 2009), the Netherlands (Van Der Klis et al., 1996), Finland (Viljakainen et al., 2006), and Denmark (Larsen et al., 2004). The relationship of serum 25OHD level to total intake of vitamin D is:
NOTE: log(total vitamin D) has been back-transformed to total vitamin D for presentation in this figure.
