Little is known about the effect of persistent depressive symptoms on the trajectory of cognitive decline.
We aimed to investigate the longitudinal association between the duration of depressive symptoms and subsequent cognitive decline over a 10-year follow-up period.
The English Longitudinal Study of Ageing cohort is a prospective and nationally representative cohort of men and women living in England aged ≥50 years. We examined 7610 participants with two assessments of depressive symptoms at wave 1 (2002–2003) and wave 2 (2004–2005), cognitive data at wave 2 and at least one reassessment of cognitive function (wave 3 to wave 7, 2006–2007 to 2014–2015).
The mean age of the 7610 participants was 65.2 ± 10.1 years, and 57.0% were women. Of these, 1157 (15.2%) participants had episodic depressive symptoms and 525 participants (6.9%) had persistent depressive symptoms. Compared with participants without depressive symptoms at wave 1 and wave 2, the multivariable-adjusted rates of global cognitive decline associated with episodic depressive symptoms and persistent depressive symptoms were faster by –0.065 points/year (95% CI –0.129 to –0.000) and –0.141 points/year (95% CI –0.236 to –0.046), respectively (P for trend < 0.001). Similarly, memory, executive and orientation function also declined faster with increasing duration of depressive symptoms (all P for trend < 0.05).
Our results demonstrated that depressive symptoms were significantly associated with subsequent cognitive decline over a 10-year follow-up period. Cumulative exposure of long-term depressive symptoms in elderly individuals could predict accelerated subsequent cognitive decline in a dose-response pattern.
Declaration of interest