Can obesity protect against cognitive impairment?

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  • Obesity was associated with lower risk of cognitive decline among middle-aged and older South Koreans.


Study design/methods

  • 5,125 participants in the Korean Longitudinal Study of Aging, age >45 with normal baseline cognitive function in 2006, underwent 6-year follow-up for change in cognitive function using the Korean Mini-Mental State Examination (K-MMSE).


Key Results

  • During follow-up, 358 participants developed severe cognitive impairment.
  • Compared with normal weight, those with baseline BMI≥25 kg/m2 were less likely to develop severe cognitive impairment (adjusted odds ratio 0.73, 95%CI 0.52-1.03; P=.03).
  • The association was stronger in women (0.63; 0.40-1.00; P=.01) and in participants with low-normal baseline K-MMSE score (24-26; 0.59; 0.35-0.98; P<.01).
  • Obese vs. normal weight participants had slower cognitive decline, especially among women and those with low-normal baseline K-MMSE score.



  • Findings might not apply to non-Korean populations.


Why this matters

  • The association of obesity with lower risk of cognitive decline raises interesting questions about underlying mechanisms and potential therapeutic targets. Given the known health risks of obesity, gaining weight is clearly not a viable preventive strategy.