Changes in dietary patterns over a 6-year period in an elderly population.
We have not employed a rigid statistical interpretation of the data in this report because, as Botwinick and Arenberg pointed out, the time span of a study (if short enough) and the number of independent observations (if small enough) can affect statistical significance. In the present study, the time span was only 6 years, and the males, as well as the females, were grouped into a single age cohort. These limitations do not allow us to assess true time effects. Nevertheless, we attributed the differences noted between the cross-sectional and longitudinal slopes to a time effect, that is, to a secular trend, over the span of the study. This conclusion was based on the following line of reasoning: First, we assumed that there were no significant cohort effects in the population considered in the present study. This assumption was supported by results from the Baltimore Longitudinal Study of Aging, where no cohort effects were found. (In the Baltimore study, 180 males were followed over a period of 15 years, and the age range covered 40 years.) Second, we documented evidence that the participants in the present study actively limited their cholesterol and fat intake because of their keen awareness of an association between cholesterol intake and coronary heart disease as reported in the lay press over the past 10 years. In the healthy male population considered in the present study, we determined that there was a decrease in daily energy intake of approximately 12 kcal/year. We based this determination on the average of the cross-sectional analysis as we attributed much of the negative effect noted in the longitudinal analysis, as stated above, to a secular trend. Aging had a much lower negative effect on energy intake in the female population, being approximately 4 kcal/year. The decrease in protein intake with age was higher in males (1.1 g/day/year) than in females (0.6 g/day/year). This finding parallels the large negative effect of aging in energy intake noted for males compared with females. The same sex difference was noted for carbohydrate intake between males and females (-0.4 and -0.2 g/day/year, respectively). The cross-sectional findings for fat intake are unremarkable for the males (no change) as well as for the females (only -0.1 g/day/year).(ABSTRACT TRUNCATED AT 250 WORDS)
Garry
P J
PJ
Department of Pathology, University of New Mexico School of Medicine, Albuquerque 87131.
Rhyne
R L
RL
Halioua
L
L
Nicholson
C
C
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001835:Body Weight; D004032:Diet / Q000639:trends*; D002149:Energy Intake; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008297:Male