Researchers at the University of California, Los Angeles (UCLA) have found that women may begin to experience age-related declines in cognitive skills as early as their 50s, earlier than suggested by previous research.
“Our results provide strong, longitudinal evidence of cognitive aging in midlife women, with substantial within-woman declines in processing speed and memory,” wrote Arun S. Karlamangla, MD, PhD, of the Division of Geriatrics, David Geffen School of Medicine at UCLA, and co-authors.
“Although cross-sectional studies suggest that cognitive aging starts in midlife, few longitudinal studies have documented within-individual declines in cognitive performance before the seventh decade,” they noted.
The research team examined data on more than 2,000 healthy, midlife women whose cognitive changes had been measured regularly over several years through the Study of Women’s Health Across the Nation (SWAN). Their median age at baseline was 54, and changes were measured up to 6 times, every 1 or 2 years.
The study was designed to account for menopause-related changes and “practice effects,” which occur when individuals learn from taking the same test repeatedly, influencing the results.
The study found a 4.9% mean decline in cognitive speed over 10 years, and a mean decline of 2% in verbal episodic memory over 10 years. It did not find longitudinal declines in immediate recall or working memory, but researchers speculated that more sensitive measurements might also find declines in those areas.
“Further research is needed to determine factors that influence differential rates of decline in cognitive performance with an eye towards developing interventions aimed at slowing cognitive aging,” the researchers concluded.
Their findings are published in the online journal PLOS ONE.
