For years, research has suggested that caffeine consumption has certain cognitive benefits (as have caffeine drinkers). Therefore, many studies investigating the cognitive effects of caffeine have recently been conducted. One of these studies examined the potential protective effect of caffeine on the development of dementia or global cognitive impairment (Driscoll et al., 2016). This article will briefly review the findings of that study.
Methods
The participants in this study consisted of 6,467 women who were enrolled in a larger clinical trial for a hormone therapy. These women all provided self-reported caffeine consumption data around their time of enrollment, which ranged from 1995-1999. The self-report measure used at baseline was the Food Frequency Questionnaire (FFQ), and all responses about coffee, tea, and cola intake were assumed to refer to the caffeinated versions, not the decaffeinated versions, of these beverages. More information on caffeine intake was collected with the Personal Habits Questionnaire (PHQ), which specifically asks about the consumption of caffeinated coffee. Based on self-reported caffeine intake, the participants were grouped into quartiles.
The participants then had their global cognitive function assessed annually through 2007 by being administered the 100-point Modified Mini Mental State (3MS) exam. Further assessment was conducted using the 40-point Telephone Interview for Cognitive Status-modified (TICSm). These assessments were aiming to measure the development of probable dementia (PD) and mild cognitive impairment (MCI) among the patients. In addition, the participants provided self-reported caffeine intake updates twice during the lengthy follow-up period.
Results
The following results were obtained:
- The mean self-reported caffeine intake at baseline was 172 mg/day, which is roughly two eight-ounce cups of black coffee.
- By the end of the study, 209 women received a classification of PD, while 388 received a classification of any impairment (composite cognitive impairment; MCI + PD).
- Higher levels of caffeine intake at baseline were associated with reduced levels of both PD and composite cognitive impairment.
- Higher levels of caffeine intake were associated with higher levels of global cognitive functioning, as assessed by 3MS scores.
Altogether, increased caffeine intake was associated with increased cognitive functioning and decreased risk of PD and composite cognitive impairment.
Wrapping up
Since this study was conducted with older women, it is assumed that their caffeine intake at baseline is somewhat representative of their lifetime caffeine intake patterns. A future study could be a longitudinal study examining the same people over decades, and that study could also be more accurate about caffeine intake to better elucidate the effect. However, it is still notable that increased caffeine intake appears to have both cognitive benefits and protective effects against cognitive impairment.
References
Driscoll, I., Shumaker, S.A., Snively, B.M., Margolis, K.L., Manson, J.E., Vitolins, M.Z., Rossom, R.C., Espeland, M.A. (2016). Relationships Between Caffeine Intake and Risk for Probable Dementia or Global Cognitive Impairment: The Women’s Health Initiative Memory Study. The Journals of Gerontology, Series A, Biological Sciences and Medical Sciences, 71(12), 1596-1602. doi: 10.1093/gerona/glw078.
