Exercise and PPARGC1A rs8192678 in Older Adults With Type 2 Diabetes and Cognitive Impairment

Association Between PPARGC1A rs8192678 Polymorphism and the Effects of a 12-Week Combined Aerobic and Resistance Exercise Intervention in Older Adults With Type 2 Diabetes Mellitus and Cognitive Impairment

This completed single-arm interventional study evaluated changes in metabolic control, cognitive function, and health-related physical fitness following a 12-week combined aerobic and resistance exercise program in older adults with type 2 diabetes mellitus and cognitive impairment. The study also explored whether the magnitude of response to exercise differed according to PPARGC1A rs8192678 genotype.

A total of 75 participants were genotyped, and 45 participants were included in a balanced genotype-stratified cohort, consisting of 15 participants with the CC genotype, 15 with the CT genotype, and 15 with the TT genotype. All participants received the same exercise intervention and were assessed at baseline and at Week 12.

This was a completed, retrospectively registered, single-arm exercise intervention study with prespecified genotype-stratified analyses. The study examined whether PPARGC1A rs8192678 genotype was associated with interindividual variation in response to a standardized combined aerobic and resistance exercise program in older adults with type 2 diabetes mellitus and cognitive impairment.

PPARGC1A rs8192678 genotyping was performed on peripheral blood DNA using Kompetitive Allele-Specific Polymerase Chain Reaction (KASP). Genotype was used as an analytical stratification factor and did not determine intervention assignment. From 75 genotyped participants, a balanced cohort of 45 participants was included, comprising 15 participants with each of the CC, CT, and TT genotypes.

All participants received the same 12-week exercise intervention. Aerobic exercise consisted of group-based aerobics performed four times per week. Aerobic exercise duration progressed from 20 minutes per session during Weeks 1-4 to 30 minutes during Weeks 5-8 and 40 minutes during Weeks 9-12. Exercise intensity progressed from 50%-60% of age-predicted maximum heart rate during Weeks 1-6 to 60%-70% during Weeks 7-12. Maximum heart rate was estimated using the equation: 207 - 0.7 × age.

Resistance exercise using elastic bands was performed twice per week. Resistance exercise duration progressed from 20 minutes during Weeks 1-4 to 30 minutes during Weeks 5-8 and 40 minutes during Weeks 9-12. Intensity progressed from 40%-50% of estimated one-repetition maximum during Weeks 1-6 to 50%-60% during Weeks 7-12. One-repetition maximum was estimated from a 10-15 repetition-maximum test using the Brzycki equation: estimated 1RM = load/[1.0278 - (0.0278 × number of repetitions)].

Exercise sessions included a 5-10-minute warm-up and cool-down period. Heart-rate monitors, supervised instruction, standardized exercise demonstrations, and safety monitoring were used to maintain the prescribed intensity and intervention quality. Measurements were obtained before the intervention and after 12 weeks. The main analysis assessed within-participant change from baseline, and exploratory analyses compared changes among genotype groups. For variables with significant baseline differences, analysis of covariance was performed using the baseline value as a covariate.

Inclusion Criteria:

1. Diagnosed with type 2 diabetes mellitus.
2. No regular exercise training during the previous six months.
3. Aged 65 to 79 years.
4. Self-reported memory decline and Montreal Cognitive Assessment score <26.
5. Stable antidiabetic medication use and stable dietary control.
6. Participant or family member provided informed consent.

Exclusion Criteria:

1. Diabetic ketoacidosis within the previous three months.
2. Visual or hearing impairment or other conditions affecting cognitive assessment.
3. Fracture, limb disability, or other motor disorders affecting exercise participation.
4. History of psychiatric disorders.
5. History of stroke, brain tumor, hypothyroidism, or other diseases that may affect cognitive function.
6. Poor compliance or failure to follow the prescribed diet or exercise requirements.