Many of our patients and their physicians are aware that physical inactivity and obesity are at epidemic proportions in the United States, which has resulted in an increased prevalence of chronic diseases. Relatively few, however, realize that both these conditions may be associated with poor memory function.
Let’s consider the issue of obesity. Over the years, obesity has truly become a woman’s issue. Sixty five million of the 72 million American adults who are considered obese or overweight are women. In addition African American and Hispanic women are much more likely to be obese than white women. So what does being obese or overweight have to do with cognition in women?
Well, recent findings from the Women’s Health Initiative, suggest that the more an older woman weighs, the poorer her memory will be. In this study, a total of 8,745 cognitively normal, post-menopausal women ages 65 to 79 underwent baseline cognitive testing as part of their routine evaluation. This study used the Modified MMSE examination ( a 100 point memory test) as the measure of cognitive function. The 3MSE has been widely used in large population based studies as a cognitive tool and has demonstrated good consistency, reliability, sensitivity and specificity for detecting cognitive impairment and dementia. For all women, both waist and hip measurements in addition to body mass index ( BMI) calculations were obtained. All the women were classified into BMI categories that corresponded to the standard World Health Organization classifications for normal weight, underweight, overweight and obesity.
The majority of women in this sample ( 86.6% white) were classified as overweight or obese ( 70%). For every one-point increase in a woman’s BMI, her memory score dropped by one point.( p<0.001). These findings were adjusted for age and educational level and remained unchanged after controlling for common chronic conditions such as diabetes, heart disease and stroke.
When the analyses included waist-hip ratio, BMI and 3MSE, the 3MSE scores for women with low waist-hip ratio decreased as the BMI category increased, although this relationship reversed for women with the highest waist-hip ratios. The 3MSE score increased (i.e. better cognition) with increasing BMI in the highest waist-hip ratio category. These results suggest that women who have a “pear shaped” body type (fat deposited around the hips) have poorer cognitive function compared to “apple shaped” body type women (fat deposited around the waist).
One explanation for these findings is that the production of endogenous estrogen (i.e. “natural” estrogen produced by the body) by abdominal adipocytes ( fat cells) may play a protective role for cognitive function and may be less detrimental than fat in other areas. Further research in this area, and whether any notable differences in the strength and nature of these associations across diverse ethnic groups, will need to be explored.
Check out the articles and links below to learn more:
- Kerwin DR, Zhang Y, Kotchen JM et al. The Cross-Sectional Relationship Between Body Mass Index, Waist-Hip Ratio, and Cognitive Performance in Postmenopausal Women Enrolled in the Women’s Health Initiative. J Am Geriatr Soc. 2010.
- Anderson GL, Manson J, Wallace R et al. Implementation of the Women’s Health Initiative study design. Ann Epidemiol. 2005.
- Healthier Chicago.org
- Strategies to Overcome and Prevent (STOP) Obesity Alliance
Thanks for reading.