[Relationship between determining factors for depressive symptoms and for dietary habits in older adults in Mexico].

OBJECTIVE: To determine the factors that are commonly associated with both the dietary habits of older adults living in the community and depressive symptoms in this group.
METHODS: Secondary analysis of data on Mexico City obtained by means of the multicenter study on Health, Well-being, and Aging (Salud, Bienestar y Envejecimiento, SABE) that was carried out in 1999 and 2000. The following variables were examined: presence or absence of depressive symptoms, according to Yesavage's Geriatric Depression Scale (GDS); mental status, as reflected by the score obtained on a modified, shortened version of Folstein's Mini-mental State Examination (MMSE); and functional capacity, as measured by Katz' Index of Independence in Activities of Daily Living. Those whose score on the shortened MMSE was 12 points or less were asked to respond to the Pfeffer Functional Activities Questionnaire, which was used to assess their ability to perform the basic activities of daily living. Information was obtained through self-report on the material, physical, psychological, and social aspects of purchasing, preparing, and consuming food products and of oral health status during the most recent 12-month period. Variables that were significantly associated with the results obtained on the GDS were included in a multivariate regression analysis; several statistical models were created, and variables that were shown to be statistically significant in the stepwise multivariate linear regression were used to determine the best-fitting explanatory model for the results obtained on the GDS.
RESULTS: The average age of study participants was 64.4 +/- 8.6 years, and the prevalence of depressive symptoms was 66%. The score obtained on the GDS showed a significant association with the presence of arterial hypertension (P < 0.01), but not with the self-reported presence of diabetes, neoplasia, stroke, lung disease or heart disease. However, the use of dental prostheses (P < 0.01), urinary incontinence (P < 0.01), and falls (P < 0.01) were significantly associated with the results on the GDS. The intake of milk products, meat, fish, fowl, fruit, and vegetables was significantly lower in the group that had depressive symptoms. An inverse correlation was detected between the score obtained on the GDS on the one hand, and the number of complete meals consumed during the day (P < 0.01) and total fluid intake (P < 0.01) on the other. The determining factors that were most closely associated with these results were, in addition to the presence of arterial hypertension, the presence of cognitive impairment (P < 0.01), difficulty performing the basic activities of daily living (P = 0.03) and the instrumental activities of daily living (P < 0.01), poor mobility (P < 0.01), difficulty using the telephone (P < 0.01), and the self-perception of having poor memory (P < 0.01), of having insufficient resources with which to live (P < 0.01), and of having poor oral health (P < 0.01). These variables explained 31% of the variance seen in the R2 values linked to the SDG variables that were incorporated into the final explanatory model.
CONCLUSION: A number of determining factors for depressive symptoms and the results obtained on the GDS resemble the factors that determine poor dietary habits among older adults. The potential existence of common causative mechanisms calls attention to the need for designing interventions aimed at preventing both types of problems and their negative consequences. These results confirm the need to take dietary habits and other parameters into account when studying depression in older adults.