Weight, income status modify impact of extreme temperature events on daily step counts

Individuals with low income or high BMI appear to be more vulnerable to heatwaves, while those with low income or normal BMI tend to have greater sensitivity during cold spells, both of which contribute to fewer daily step counts, suggests a study.

Researchers conducted a longitudinal panel study in Henan Province, China, to examine the relationship between extreme weather events and daily step counts by body weight and to determine whether these associations are modified by sociodemographic factors.

Distributed lag nonlinear models were used to establish how daily step counts were influenced by weather events (eg, heatwaves and cold spells) and their intensity and duration.

Extreme weather events substantially reduced step counts. Specifically, heatwaves correlated with a significant decrease in daily step counts among individuals with overweight (‒959.68 steps, 95 percent confidence interval [CI], ‒1,198.13 to ‒721.22), which was much larger than the decline seen in those with normal weight (‒331.16 steps, 95 percent CI, ‒625.50 to ‒36.83).

In contrast, cold spells showed an association with a disproportionately greater decrease in step counts among individuals with normal weight (‒1,832.46 steps, 95 percent CI, ‒2,136.15 to ‒1,528.76) relative to a milder decrease in those with overweight (‒1,067.66 steps, 95 percent CI, ‒1,317.40 to ‒817.91).

“Interaction analysis revealed that high income consistently attenuated these disparities (p<0.05 for interaction),” the researchers said. “Although age and sex also modified these associations, body weight emerged as a primary factor.”