Risk for Type 2 Diabetes Mellitus Person, Place, and Precision Prevention

Unprecedented increases inobesity in theUnitedStateshave contributed to greater prevalence of diseases, such as type 2 diabetesmellitus (T2DM),which impair the quality of life and reduce the longevity of affected individuals, createdemands on already-strained health care delivery systems, and generate greater health care costs. Observations gleaned from earlier successes in reducing the rates of smoking and smoking-related diseases can inform efforts to reverse this trend. However, smoking reductions were not accomplished primarily by health care activities. Although interventions in primary care settings played an important role,1 other actions, ranging from media campaigns to policies involvingadvertisingbans, taxation,andsmoke-freeareas, were critical to changing the dynamics of cigarette use. The behavioral causesofobesity—diet andexercise—areevenmore strongly rooted in factors outside thehealth care system.Traditionalmedical treatments alone cannot substantially lower the prevalence and impact of obesity without changes in the obesogenicenvironment.Addressingenvironmental causes recasts diet and exercise as behaviors that are not only a function of individual choice and will power but that are strongly shapedby the resources andobstacles encountered in the environments in which behaviors are enacted.2 The neighborhood effects measured by Christine and colleagues3 documented that individuals residing inneighborhoodsmarkedby limited resources for healthy eating andphysical activity (PA) are at higher risk for being diagnosed with T2DM. Based on a rigorous prospective, longitudinal design, their research substantiates the claim that the physical and social contexts of neighborhood environments matter for disease onset. Althoughwedonot yet knowwhat elements of neighborhoodsaremost essential for generatingbetterhealth, these researchersprovide important clues aboutwhichelementshave an effect and for whom. One notable finding was that T2DM onset was not predicted by objective measures of the physical environment (eg, geographic information system–based counts of the density of food stores and commercial recreational facilities) but by shared perceptions of people in the community regarding the availability of healthy food and nearby places to be active. This result is consistentwith those of other studies that found relatively weak associations between the proximity of supermarkets and outcomes such as bodymass index (BMI) and fruit andvegetable consumption.4 Unless the available resources are widely known and viewed as accessible, “if you build it, they will come”may not apply. A second informative findingwas that environmental resources were differentially related to T2DM risk for individualswithhighervs lower incomes.Low-incomeparticipants living in areas viewed as having less social cohesion and being less safe for walkingweremore likely to develop T2DM. Such viewswere less relevant for high-income individuals. The latter may not need to worry about the social climate of their neighborhoods in relation to PA. Financial resources enable them to join fitness centers that provide safe spaces for exercise,whatever theirneighborhoodenvironment is like. In contrast, lower-income individuals have fewer options for exercise. They may not be able to afford gym fees, and concern about thesafetyof their areamay inhibitoutdooractivity.Lowincome individuals residing in neighborhoods with less social cohesionmayalsoencountermore threat andconflict, and theresultingchronicstresscould independently increaseT2DM risk through effects on sleep, eating, and neuroendocrine response.5 Although safety and social cohesionmore strongly predicted T2DM onset for lowthan high-income individuals, resources forPAweremorestrongly linked toT2DMamong highthan low-income individuals.This findingemerged from the researchers’ use of a geographic information system– basedmeasureof resources that includedonly commercial establishments. The cost of using these facilitiesmay have renderedtheminaccessible to thosewith less income,makingtheir physical proximity irrelevant.Access to freeor low-cost gyms, parks, swimming pools, and safe places to walk or runwould probably bemore likely to contribute to increasing PA among low-income individuals than proximity to commercial establishments. Overall, measures of the food environment were less strongly related to T2DM onset than were PA resource measures. This result could reflectmeasurement differences, but diet might be harder to modify via neighborhood resources than exercise. Food preferences and practices may be established earlier in life and shaped by other factors, such as the relative cost of healthy vs unhealthy foods, even if both are physically proximal. In sum, the findings by Christine et al3 point to the impactofperceivedneighborhoodresources.Havingmarketsand recreational facilities locatednearbymaybenecessarybutnot sufficient to enable healthy behaviors. Building more facilities inneighborhoods that lack themisacomponentofanoverall strategy toaddress thenational rise inobesity, but this strategy needs to be informed by an understanding of when such facilities are actually used and the characteristics of the individuals who use them. In brief, the risk for T2DM is a combination of both person and place, and our national strategies need to understand and intervene across these levels. A multilevel approach that encompasses an understandingofpersonandplace is equallypertinent for providingmore effectivehealth care andcouldbuildon the conceptual framework underlying precision medicine.6 Precision medicine is Related article page 1311 Association Between Neighborhood Environments and Type 2 Diabetes Mellitus Original Investigation Research