Serum levels and liver store of retinol and their association with night blindness in individuals with class III obesity.

BACKGROUND

Studies showed a rise in obesity prevalence in world population and evidences point to a possible association with vitamin A deficiency (VAD). The objective of this study is to assess vitamin A nutritional status through functional [night blindness diagnosis-xerophthalmia (XN)] and biochemical (serum levels and retinol liver store) indicators of class III obesity individuals and its association.

METHODS

We studied 114 patients of both genders with BMI ≥40 kg/m2, candidates to bariatric surgery at Clínica Cirúrgica Carlos Saboya in Rio de Janeiro, Brazil. XN was diagnosed through a standardized interview (WHO and MacLaren and Frigg), and serum levels and retinol liver store were quantified by HPLC-UV with <1.05 μmol/L and < 20 mg/g cutoffs for VAD, respectively.

RESULTS

XN prevalence was 23.8%, and serum levels and retinol liver store inadequacy were 14.0% and 80%, respectively. The association between VAD and XN presence (p = 0.003) was observed with the biochemical indicator and the gold standard, retinol liver store (p = 0.003 and p = 0.018, respectively). Means were 59.3% (sensitivity), 87.4% (specificity), and 80.8% (accuracy) as regards to the XN role in predicting VAD according to the biochemical indicator. As regards to retinol liver store, XN diagnosis presented 48% of sensitivity and 75% of specificity. VAD highest indexes occurred in patients with highest BMI (rs-0.21, p = 0.02). Distribution of XN prevalence was 59.2% according to serum retinol.

CONCLUSIONS

VAD and XN prevalence was high in class III obesity individuals, and the functional indicator for XN diagnosis may be a promising method for diagnosis in this group.