medwireNews: The increased risk for prediabetes among ethnic minorities compared with White people is less pronounced in neighborhoods with high walkability, shows a Canadian study.
Ghazal Fazli (St Michael’s Hospital, Toronto, Ontario) and co-researchers followed up 267,529 immigrants and 860,652 long-term residents in 15 municipalities in Southern Ontario from 2002 through 2011. During this time, 50,971 of the immigrants developed prediabetes, defined according to the World Health Organization criteria.
The researchers divided people into small neighborhood units of approximately 400–700 people and calculated a walkability index for each, based on factors such as residential density and availability of facilities within walking distance. They found that the incidence rate of prediabetes was higher among immigrants who lived in neighborhoods in the lowest 10th of the walkability index versus the highest, at 3.48 versus 3.30 per 100 person–years, equating to a significant 20% risk increase.
There was also a significant 15% increased risk for prediabetes among long-term residents living in the least versus most walkable neighborhoods. These associations were independent of variables including age, sex, area income, ethnicity, education, and marital status.
However, Fazli and team stress that “the associations between walkability and pre-diabetes incidence varied across ethnic groups for reasons that were unclear.”
People of sub-Saharan-African/Caribbean, Southeast Asian, Latin American, or West Asian/Arab descent all had a significantly increased risk for developing prediabetes if they lived in a neighborhood with the lowest versus highest walkability, with risk increases ranging from 17% to 32%.
But neighborhood walkability had no effect on prediabetes risk in people of South Asian, East Asian, and Eastern European descent, and appeared to have the reverse effect in Western Europeans, who were significantly more likely to develop prediabetes if they lived in a more walkable neighborhood.
The researchers suggest this may stem from varying ethnic attitudes toward different forms of exercise, as well as other local factors such as safety, healthy food access, and social support.
“Hence, neighborhoods that support healthy living may be necessary, but perhaps not sufficient to enable all residents to be healthy and active,” they say.
Nonetheless, the team found that while all ethnicities bar Eastern Europeans had a significantly higher prediabetes risk than White Europeans if they lived in a neighborhood with low walkability, this risk was much reduced for most ethnicities living in neighborhoods with high walkability.
Specifically, only people of South Asian, Southeast Asian, and sub-Saharan-African/Caribbean descent remained at significantly increased risk, and the risk increase was 1.23- to 2.10-fold rather than 2.07- to 2.40-fold.
“[W]hile these findings may appear intuitive, randomized trials in this field are not feasible,” write the researchers in BMJ Open Diabetes Research & Care, and “thus, it is not known whether policies that increase neighborhood walkability would in fact translate into fewer cases of diabetes.”
They believe “[t]he growing enthusiasm among city planners to adopt healthy urban designs provides an opportunity for researchers to study the effects of such natural experiments on diabetes and related diseases,” but caution that “built environment interventions alone are unlikely to be effective in all populations.”
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