Prevalence of bipolar disorder in a sample of older adults

Abstract

***Prevalence of bipolar disorder in a sample of older adults***AIMS: To estimate the prevalence of bipolar disorder in a sample of older adults and to examine associated socio-demographic and clinical factors.METHODS: Cross-sectional population-based study of individuals aged 60 years or older registered with the Family Health Strategy in Porto Alegre, Rio Grande do Sul, Brazil, selected randomly from 30 different basic health units. Participants were subjected to diagnostic assessment for bipolar disorder and suicide risk using the Mini International Neuropsychiatric Interview Plus 5.0.0. Categorical variables were described as absolute and relative frequencies. Quantitative variables were expressed as means and standard deviations. The Pearson chi-square or Fisher’s exact tests were used as appropriate to evaluate potential associations between the independent variables suicide attempt and risk of suicide. To control for possible confounders and assess variables independently associated with the outcome of interest, the strength association among different risk factors was assessed by means of prevalence ratios, which were estimated with a controlled Poisson model or multivariate Poisson regression. The significance level was set at 5% (p≤0.05).RESULTS: The sample comprised 550 older adults. The lifetime prevalence of bipolar disorder in the sample was 5.8% and the point prevalence was 1.5%. In those with bipolar disorder, 59.4% were type I and 40.6% type II. Significant associations were observed between bipolar disorder regardless of type and female gender (prevalence rate [PR] 2.42, 95% confidence interval [CI] 1.01-5.81), living with a partner (PR 2.52, 95%CI 1.21-5.24), history of suicide attempt (PR 3.16, 95%CI 1.53-6.25), and suicide risk (PR 2.98, 95%CI 1.47-6.06). When analyzed each type of bipolar disorder, statistically significant associations were found between age under 70 years and type I bipolar disorder; having companion and type II bipolar disorder; and risk of suicide was associated with both types of bipolar disorder.CONCLUSIONS: Regardless of the type of bipolar disorder, women and those living with a partner were more affected. History of suicide attempts and suicide risk were more frequent in elderly subjects with bipolar disorder than in those without the disorder.