What This Means
This study followed Chinese adults aged 50 and older to see how their overall physical and mental functioning, called intrinsic capacity, changes over time. Intrinsic capacity combines mobility, thinking, mood, vision and hearing, and vitality. The researchers found that people fall into four groups: some stay high and stable, some start high and decline slowly, and two groups decline rapidly from moderate or low starting levels.
Older age, being female, having multiple chronic conditions, low income, having a father with little education, and higher physical risk scores were linked to a greater chance of being in the worst group (low and rapidly declining). Using clean cooking fuel and being married were linked to a lower chance of being in that group. Age mattered most overall, but income, cooking fuel, temperature, humidity, sex, education and chronic illness also contributed.
This research suggests that functional decline in later life is not uniform and that factors beyond medical conditions, such as household environment and social circumstances, are associated with it. Because this is an observational study, it shows associations rather than proof of cause. It does point to cooking fuel and environmental conditions as potentially modifiable factors that could be considered in healthy ageing strategies.