METHODS: We conducted a two-stage time-stratified case-crossover study to examine the association between temperature and under-five mortality, spanning the period from 2014 to 2018 across all six regions in Malaysia. In the first stage, we estimated region-specific temperature-mortality associations using a conditional Poisson regression and distributed lag nonlinear models. We used a multivariate meta-regression model to pool the region-specific estimates and examine the potential role of local characteristics in the association, which includes geographical information, demographics, socioeconomic status, long-term temperature metrics, and healthcare access by region.
RESULTS: Temperature in Malaysia ranged from 22 °C to 31 °C, with a mean of 27.6 °C. No clear seasonality was observed in under-five mortality. We found no strong evidence of the association between temperature and under-five mortality, with an "M-" shaped exposure-response curve. The minimum mortality temperature (MMT) was identified at 27.1 °C. Among several local characteristics, only education level and hospital bed rates reduced the residual heterogeneity in the association. However, effect modification by these variables were not significant.
CONCLUSION: This study suggests a null association between temperature and under-five mortality in Malaysia, which has a tropical climate. The "M-" shaped pattern suggests that under-fives may be vulnerable to temperature changes, even with a small temperature change in reference to the MMT. However, the weak risks with a large uncertainty at extreme temperatures remained inconclusive. Potential roles of education level and hospital bed rate were statistically inconclusive.
METHODS: Data for this study came from the four waves of the China Health and Retirement Longitudinal Survey. A latent growth model was used to analyze the functional disability of 5044 older adults aged 60 and over in 2011 who survived to 2018.
RESULTS: Pathologies are closely associated with functional disability trajectories, and higher numbers of comorbidities relate to more disabilities. Risk factors and intra- and extra-individual factors affect functional disability trajectories and work through independent and shared mechanisms. The effects of risk factors can be traced to childhood conditions, and higher childhood and adulthood socioeconomic status is related to fewer functional disabilities.
CONCLUSION: Functional disability trajectories are dynamic processes related to pathologies, intra-, and extra-individual factors, and life-course risk factors, and thus prevention and control measures should focus on both childhood and adulthood. Promoting working in later life and improving childhood socioeconomic status deserve prompt attention. Geriatr Gerontol Int 2023; 23: 817-829.