Association of Type 2 Diabetes Subgroups With Cognitive Status Without Modification From Lifestyle Intervention

Abstract

Context: Type 2 diabetes is a risk factor for incident dementia but whether risk and treatment/prevention strategies differ by diabetes subgroup is unknown.

Objective: We assessed (1) whether specific type 2 diabetes (T2D) subgroups are associated with mild cognitive impairment (MCI) or probable dementia (PD), and (2) whether T2D subgroups modified the association of the Action for Health in Diabetes (Look AHEAD) multidomain intensive lifestyle intervention (ILI) with MCI/PD.

Methods: We included 3760 Look AHEAD participants with T2D and overweight or obesity randomly assigned to 10 years of ILI or diabetes support and education. We used k-means clustering techniques with data on age of diabetes diagnosis, body mass index, waist circumference, and glycated hemoglobin (HbA1c) to characterize diabetes subgroups at randomization. Prevalent MCI/PD were centrally adjudicated based on standardized cognitive tests and other health information 10 to 13 years after randomization. We estimated marginal probabilities for prevalent MCI/PD among T2D subgroups with adjustment for potential confounders and attrition and examined whether ILI modified any associations.

Results: Four distinct T2D subgroups were identified, characterized by older age at diabetes onset (43% of sample), high HbA1c (13%), severe obesity (23%), and younger age at onset (22%). Unadjusted prevalence of MCI/PD (314 cases, 8.4%) differed across T2D subgroup (older onset = 10.5%, severe obesity = 9.0%, high HbA1c = 7.9%, and younger onset = 4.0%). Adjusted probability for MCI/PD within T2D subgroup was highest for the severe obesity subgroup and lowest for the younger onset subgroup but did not differ by ILI arm (interaction P value = 0.84).

Conclusions: Among individuals with T2D and overweight or obesity, probability of MCI/PD differed by T2D subgroup. Probability of MCI/PD was highest for a subgroup characterized by severe obesity.

Clinicaltrials.gov identifier: NCT00017953.

Keywords: intensive lifestyle intervention; mild cognitive status and probable dementia; type 2 diabetes subgroups.

Figure 1.

Clustering variables according to diabetes subgroup in the Look AHEAD cohort. The distribution presented for each characteristic includes the minimum, 25th percentile, 50th percentile (median), 75th percentile, and maximum value.