Le rôle de la qualité alimentaire dans la prévention du déclin de l’autonomie fonctionnelle chez les personnes âgées atteintes du diabète type II faisant partie de la cohorte NuAge

The population is aging, and aging increases the risk of muscle strength (MS) loss, type II diabetes (T2D), and decline in functional capacity (FC). Independent of aging, diabetic older adults (OA) are at increased risk of MS loss and FC decline compared to their non-diabetic counterparts. Nutrition is a determinant of optimal aging, and is important in managing diabetes, and preventing, or at least slowing, the rate of development of diabetes complications; it also minimizes MS losses and finally, modulates decline in FC. In addition, physical activity (PA) offers benefits similar to those conferred by nutrition. Therefore, the main objective of this thesis is to determine the role of diet quality (DQ) in FC maintenance in community-dwelling diabetic OA in secondary analyses of the NuAge cohort database. In order to achieve this objective, characterization of several variables associated with FC was necessary. Thus, a descriptive analysis of the diet of these diabetic older adults was undertaken as our first objective. Then, the three articles are presented, each testing a specific objective in these diabetic OA, to: 1) determine if DQ alone, or combined with PA, is associated with MS maintenance; 2) determine if DQ alone, or combined with PA is associated with prevention of FC decline; and 3) examine the association between adequate protein and energy intakes and MS and FC maintenance. In addition, the association between DQ, PA and physical performance (PP) was studied. This doctoral thesis is the first to study the role of DQ on FC in diabetic OA. The results have demonstrated that diabetic OA in the NuAge cohort have a good diet overall and good dietary habits, and macronutrient intakes that meet nutrition recommendations. Nevertheless, these participants should increase their micronutrient intakes since the majority did not meet recommendations. Moreover, DQ alone was not associated with MS, PP or FC declines over the three year follow-up. However, DQ combined with PA showed associations with upper body MS. Specifically, good DQ combined with maintenance of PA over follow-up was associated with minimal MS losses in diabetic older men compared to others. However, no significant results were found for lower body MS in either males or females. Furthermore, DQ combined with PA was not associated with either PP or FC in these participants. Finally, our results have shown that adequate energy and protein intakes are associated with FC maintenance. In fact, diabetic older men with energy intakes of 30 kcal or greater/kg body weight experienced lesser declines in FC compared to those having inadequate energy intakes, while diabetic older women with protein intakes of 1g or more/kg body weight had minimal declines in FC compared to those with inadequate protein intakes. Finally, we have shown that adequate protein intakes minimized lower body MS losses in diabetic women in the NuAge cohort.  Taken together, the results of this thesis provide evidence that good DQ, adequate energy and protein intakes and the practice of PA are all factors that can minimize MS losses related to aging and accelerated by T2D, and hence maintain FC in diabetic OA. Nevertheless, further research is needed to confirm these results.

Keyphrases: Nutrition, Exercice, Aging, Type II diabetes, Nutrition, Diet quality, Exercise, Muscle strength, Functional capacity, NuAge cohort