Low Vitamin D in Candidates for Bariatric Surgery: Are the Americans Better Off than the French?

Excerpt

We read with interest the article by Dr. Ducloux and colleagues in which the authors demonstrate that 96% of patients presenting for bariatric surgery in France are vitamin D deficient [1]. We recently conducted a study in 340 morbidly obese patients presenting for bariatric surgery at the Center of Minimally Invasive Surgery at St. Luke’s-Roosevelt Hospital in New York. Only 65% of the NY patients were vitamin D deficient using the same cutoff point of 50 nmol/L, and their mean vitamin D level was substantially higher compared to that of patients in France (47 ± 26 nmol/L versus 31 ± 13 nmol/L). The NY patients were ethnically diverse with 43% Hispanics, 30% African–Americans, and 27% Caucasians. In contrast with Ducloux et al., we found differences in vitamin D levels between ethnic groups (P < 0.001, ANOVA with Tukey’s post hoc tests). African–Americans had lower levels of vitamin D (39 ± 17 nmol/L) than both Caucasians (55 ± 25 nmol/L, P < 0.001) and Hispanics (49 ± 30 nmol/L, P = 0.006). In addition, vitamin D levels were negatively correlated with BMI (P = 0.017, r = −0.130) and strongly associated with ethnicity. Only 24% of African–Americans presenting for bariatric surgery had vitamin D levels≥50 nmol/L, versus 34% of Hispanics and 48% of Caucasians (P < 0.001 by the chi-square test). In Ducloux’s patients, the absence of associations between ethnicity, BMI, and vitamin D levels may be due to the small number of patients studied (n = 50). One can only speculate why the vitamin D levels are substantially lower in the Parisian French than in American patients [2]. Sun exposure may have been different between the two independently studied cohorts; however, this was found not to be an important factor in Ducloux’s and Goldner’s studies. …