Paradoxical Relationship Between Glycated Hemoglobin and Longitudinal Change in Physical Functioning in Older Adults: A Prospective Cohort Study.

BACKGROUND: Hyperglycemia with high hemoglobin A1c (HbA1c) levels is associated with significant health risks. However, the relationship between HbA1c levels and the physical functioning status in later life remains uncertain and so is the possible underlying mechanism. METHODS: We conducted a prospective study of 2,565 initially well-functioning community-dwelling older adult aged 55 years and older from the Healthy Aging Longitudinal Study in Taiwan. Each participant received baseline measurements of blood HbA1c and inflammatory markers levels and repeated assessments of physical functioning over a mean follow-up period of 5.3 years. We used generalized linear mixed-effects regression to estimate the adjusted changes in the odds ratio for self-reported physical functioning impairment and Short Physical Performance Battery (SPPB) score according to baseline HbA1c levels (categorized into 0.5% increments from <5.5% to ≥7.0%). RESULTS: HbA1c levels showed a U-shaped relationship with changes in the odds ratio for physical functioning impairment and SPPB score (p for quadratic term < .001). Compared with participants with an HbA1c of 5.5% to <6.0%, those with an HbA1c of <5.5% or ≥7.0% had a higher annual increase in the odds ratio for physical functioning impairment (odds ratio [95% confidence interval] per year, 1.25 [1.04-1.50] and 1.21 [1.04-1.41]) and a higher annualized decrease in SPPB score (coefficient [95% confidence interval], -0.05 [-0.10 to 0.00] and -0.04 [-0.08 to 0.00]). These relationships were nonlinear only in participants with high soluble interleukin-6 receptor levels (>48,124 pg/mL; p for interaction < .05). CONCLUSIONS: High and low HbA1c levels at baseline are associated with faster physical functioning decline, particularly among individuals with elevated circulating soluble interleukin-6 receptor, a sign of enhanced interleukin-6 trans-signaling.

Healthy lifestyle and normal waist circumference are associated with a lower 5-year risk of type 2 diabetes in middle-aged and elderly individuals: Results from the healthy aging longitudinal study in Taiwan (HALST).

Type 2 diabetes mellitus (DM) is known to be closely associated with lifestyle and obesity and has a prevalence that increases with age. This study aimed to assess the short-term composite effect of diet, physical activity, psychosocial health, and waist circumference (WC) on the incidence of DM in the elderly and to provide a lifestyle-based predictive index.We used baseline measurements (2009-2013) of 5349 community-dwelling participants (aged 55 years and older, 52% female) of the Healthy Aging Longitudinal Study in Taiwan (HALST) for fasting plasma glucose, HbA1C, serum cholesterol, triglycerides, blood pressures, WC, and outcomes of home-visit questionnaire. Principal component analysis (PCA) was used to identify participants with a healthy lifestyle (HLF: higher diet, physical activity, and psychosocial scores) and a lower WC, with cutoffs determined by the receiver-operating characteristics. A Cox regression model was applied to 3424 participants without DM at baseline by linking to their National Health Insurance records (median follow-up of 3.1 years).In total, 247 new DM cases (7.2%) were identified. The HLF and lower WC group had a relative risk (RR) of DM of 0.54 (95% CI 0.35-0.82) compared to the non-HLF and higher WC group. When stratified by the presence of impaired glucose tolerance (IGT) or metabolic syndrome (MS), only participants with IGT/MS showed significant risks (RR 0.55; 95% CI 0.33-0.92). However, except for WC, the individual lifestyle factors were nonsignificant in the overall model without PCA.A composite protective effect of HLF and normal WC on DM within 5 years was observed, especially in those with IGT or MS. Psychosocial health constituted an important lifestyle factor in the elderly. The cutoffs identified could be used as a lifestyle-based risk index for DM. Maintaining an HLF to prevent DM is especially important for the elderly.