To evaluate the frequency of nutritional, metabolic and endocrine disorders in patients with bipolar disorder (BD).

A Medline search (up to January 2008) in and manual review of reference lists of relevant primary articles and review articles. All studies in Spanish or English, all study designs, BD diagnosis by any criteria, with a sample size of ≥ 30 patients, and which reported any measure of frequency measure or association.

Thirty studies were identified: 18 (60%) cross-sectional and 12 (40%) retrospective cohort; 2 (6.7%) population- based; and 2 (6.7%) random sampling. The frequency of obesity in patients with BD was higher than that of the general population (n=4, 19-53% vs 9-14%), of other medical populations (n=1, 4.6% vs 1.1%) and of patients with schizophrenia (n=1, 11.6% vs 9.9%). The frequency of diabetes in patients with BD was higher than (n=5, 6-26% vs 2-16%) or similar to (n=2, 3.5-4.3% vs 3.4-4.8%) that of the general population; higher than that of other medical samples (n=2, 1.8-4.4% vs 0.6-2.2%) and similar to that in of patients with schizophrenia (n=1, 17.7% vs 17.6%). The frequency of dyslipidaemia was higher than that found in a medical sample (n=1, 0.9% vs 0.3%) and in patients with schizophrenia (n=1, 27% vs 23%). The frequency of hypothyroidism was higher than that of a medical sample (n=1, 10% vs 3%).

BD appears to be associated with obesity. It may also be associated with dyslipidaemia and hypothyroidism. Data on the association between BD and diabetes are inconclusive.