Using admixture analysis to examine birth-cohort effects on age at onset of bipolar disorder

作者：Golmard J L; Scott J; Etain B; Preisig M; Aubry J M; Henry C; Jamain S; Azorin J M; Leboyer M; Bellivier F^*

来源：Acta Psychiatrica Scandinavica, 2016, 133(3): 205-213.

DOI：10.1111/acps.12478

• bipolar I disorder
• age at onset
• birth-cohort effect

ObjectiveIt is suggested that age at onset (AAO) of bipolar I disorder (BP-I) is decreasing. We tested for a birth-cohort effect on AAO using admixture analysis.
MethodA clinical sample of 3896 BP-I cases was analysed using two approaches: (i) in a subsample with untruncated AAOxbirth year distribution (n=1865), we compared the best-fitting model for the observed AAO in patients born 1960 and >1960, (ii) to control for potential confounders, two separate subsamples born 1960 and >1960 were matched for age at interview (n=250), and a further admixture analysis was undertaken.
ResultsThe two approaches indicated that the proportion of cases in the early AAO category was significantly greater in cases born >1960; manic onsets were also more frequent in the early onset BP-I cases born >1960.
ConclusionThe decrease in AAO of BP-I in recent birth-cohorts appears to be associated with an increase in the proportion of cases in the early onset subgroup; not with a decrease in the mean AAO in each putative subgroup. This could indicate temporal changes in exposure to risk factors for mania.

• 出版日期2016-3