Motorized transportation, social status, and adiposity: the China Health and Nutrition Survey

Trends in the prevalence of overweight, obesity, and abdominal obesity among Chinese adults between 1993 and 2015

BACKGROUND

Most previous studies on trends in the prevalence of obesity or abdominal obesity in Chinese adults were based on regional data and/or short time intervals, and recent trends are not available. We aimed to examine the secular trends in the prevalence of overweight, obesity, and abdominal obesity among Chinese adults at the national level from 1993 to 2015.

METHODS

A total of 70,242 Chinese adults aged 18-80 years were from the cross-sectional surveys conducted from 1993 to 2015. According to the World Health Organization criteria, overweight was defined as body mass index (BMI) ≥23.0 kg/m² and <27.5 kg/m², and obesity was defined as BMI ≥27.5 kg/m². According to the International Diabetes Federation criteria, abdominal obesity was defined as waist circumference (WC) ≥90 cm for men and ≥80 cm for women. Mean values and prevalence of adiposity markers were standardized to the age distribution of the China population in 2010.

RESULTS

Between 1993 and 2015, and based on age-standardized values, mean BMI increased from 21.9 kg/m² in 1993 to 23.9 kg/m² (+2.0 kg/m²) in 2015 (P for trend < 0.001), and mean WC increased from 76.0 cm to 83.4 cm (+7.4 cm) (P for trend <0.001). From 1993 to 2015, the prevalence increased from 26.6% to 41.3% (+14.7%) for overweight, from 4.2% to 15.7% (+11.5%) for obesity, and from 20.2% to 46.9% (+26.7%) for abdominal obesity (all P for trends < 0.001). In multivariate linear regression analysis, time (calendar years), older age and urban regions were strongly and independently associated with BMI.

CONCLUSIONS

The prevalence of overweight, obesity, and abdominal obesity increased markedly among Chinese adults during the past two decades. Weight control programs and public health measures to address the societal causes of obesity should be strengthened.

Physical activity and weight following car ownership in Beijing, China: quasi-experimental cross sectional study

OBJECTIVE

To determine the implications of car ownership for physical activity and weight in a global city.

DESIGN

Quasi-experimental cross sectional study.

SETTING

Beijing, China, 2011-15.

PARTICIPANTS

People aged 18 and older from a random sample of households who had entered a permit lottery to purchase a vehicle between January 2011 and November 2015.

INTERVENTIONS

Permit allowing purchase of a vehicle within six months of permit issuance.

MAIN OUTCOME MEASURES

Transit use (number of subway and bus rides each week), physical activity (minutes of walking or bicycling each day), and weight, measured once in early 2016.

RESULTS

Of 937 people analysed in total, 180 had won a permit to purchase a new vehicle. Winning the permit lottery resulted in the purchase of an additional vehicle 91% of the time (95% confidence interval 89% to 94%; P<0.001). About five years after winning, winners took significantly fewer weekly transit rides (-2.9 rides (-5.1 to -0.7); P=0.01) and walked and cycled significantly less (-24.2 minutes (-40.3 to -8.1); P=0.003) than those who did not win the lottery. Average weight did not change significantly between lottery winners and losers. Among those aged 50 and older, however, winners' weight had increased relative to that of losers (10.3 kg (0.5 to 20.2); P=0.04) 5.1 years after winning.

CONCLUSIONS

These data indicate that vehicle ownership in a rapidly growing global city led to long term reductions in physical activity and increase in weight. Continuing increases in car use and ownership in developing and middle income countries could adversely affect physical health and obesity rates.

Associations between active travel and physical multi-morbidity in six low- and middle-income countries among community-dwelling older adults: A cross-sectional study

BACKGROUND

There is little evidence on the potential health benefits of active travel in low- and middle-income countries (LMICs). The aim of this study was to assess the association between levels of active travel and physical multi-morbidity (i.e., two or more chronic physical conditions) and individual physical conditions among community-dwelling adults aged 65 or older in six LMICs.

METHODS

Data were analyzed from the World Health Organization's Study on Global Ageing and Adult Health (China, Ghana, India, Mexico, Russia, South Africa). Active travel (minutes / week) was assessed with questions of the Global Physical Activity Questionnaire (GPAQ) and presented in tertiles. Eleven chronic conditions (angina, arthritis, asthma, chronic back pain, chronic lung disease, diabetes, edentulism, hearing problems, hypertension, stroke, visual impairment) were assessed by self-report of diagnosis, symptoms, or blood pressure measurement. Multivariable logistic regression analysis was conducted to assess the association between levels of active travel, physical conditions and physical multi-morbidity.

RESULTS

The final sample consisted of 14,585 individuals aged ≥65 years (mean age = 72.6±0.1 years; 54.9% female). In the fully adjusted model, compared to the highest tertile, those in the lowest tertile of active travel had a 1.28 (95%CI = 1.06-1.54) times higher odds for physical multi-morbidity. The association between active travel and physical multi-morbidity was significantly mediated by affect (14.4%) and cognition (9.7%). With regard to individual conditions, hearing problems, hypertension, stroke, and visual impairment were particularly strongly associated with less active travel.

CONCLUSION

The current data suggest that lower levels of active travel are associated with the presence of physical health conditions and physical multi-morbidity. This multi-national study offers potentially valuable insight for a number of hypotheses which may influence this relationship, although testing with longitudinal studies is needed.

New Evidence on the Effect of Medical Insurance on the Obesity Risk of Rural Residents: Findings from the China Health and Nutrition Survey (CHNS, 2004-2011)

The obesity rate in China has risen significantly in the past few decades. While a number of causes for the rise in obesity have been explored, little attention has been paid to the role of health insurance per se. This study aims to investigate the impact of health insurance on the risk of obesity in rural China using longitudinal data from the China Health and Nutrition Survey (CHNS). We employed pooled ordinary least squares (OLS), probit estimation, and pooled two-stage least squares (2SLS) for an instrumental variable (IV). The IV model revealed that New rural cooperative medical insurance (NRCMS) participation had a significant positive impact on people's tendency towards unhealthy lifestyles, for instances, high-fat food (8.01% for female and 7.35% for male), cigarette smoking (25% for male), heavy drinking (25% for female), sedentary activity (6.48 h/w for female and 6.48 h/w for male), waist circumference (1.97 cm for female and 1.80 cm for male), body mass index (0.58 kg/m² for female), which in turn leads to an elevated probability of general obesity (51% for female) and abdominal obesity (24% for female and 20% for male). An "ex ante moral hazard" is prevalent in rural China, which should not be ignored by policymakers so as to minimize the related low efficiency in the process of promoting the universal coverage of insurance.

Factors of physical activity among Chinese children and adolescents: a systematic review

Background

Lack of physical activity is a growing problem in China, due to the fast economic development and changing living environment over the past two decades. The aim of this review is to summarize the factors related to physical activity in Chinese children and adolescents during this distinct period of development.

Methods

A systematic search was finished on Jan 10^th, 2017, and identified 2200 hits through PubMed and Web of Science. English-language published studies were included if they reported statistical associations between factors and physical activity. Adapted criteria from the Strengthening The Reporting of OBservational studies in Epidemiology (STROBE) statement and evaluation of the quality of prognosis studies in systematic reviews (QUIPS) were used to assess the risk of bias of the included studies. Related factors that were reported in at least three studies were summarized separately for children and adolescents using a semi-quantitative method.

Results

Forty two papers (published 2002–2016) were included. Most designs were cross-sectional (79%), and most studies used questionnaires to assess physical activity. Sample size was above 1000 in 18 papers (43%). Thirty seven studies (88%) showed acceptable quality by methodological quality assessment. Most studies reported a low level of physical activity. Boys were consistently more active than girls, the parental physical activity was positively associated with children and adolescents’ physical activity, children in suburban/rural regions showed less activity than in urban regions, and, specifically in adolescents, self-efficacy was positively associated with physical activity. Family socioeconomic status and parental education were not associated with physical activity in children and adolescents.

Conclusions

The studies included in this review were large but mostly of low quality in terms of study design (cross-sectional) and methods (questionnaires). Parental physical activity and self-efficacy are promising targets for future physical activity promotion programmes. The low level of physical activity raises concern, especially in suburban/rural regions. Future research is required to enhance our understanding of other influences, such as the physical environment, especially in early childhood.

Electronic supplementary material

The online version of this article (doi:10.1186/s12966-017-0486-y) contains supplementary material, which is available to authorized users.

Emerging adults without a driver's license engage in more transportation-related physical activity to school/work in certain environmental contexts

The aim was to examine the moderation effect of driving licensure status on the association between different environmental contexts and transportation-related physical activity to and from school and/or work (TPA-SW) among emerging adults. The data were from Wave 4 (n=2026, year 2013) of the NEXT Generation Health Study, an annual assessment of a nationally representative cohort across the nine U.S. Census Divisions. The outcome variable, TPA-SW, was derived from walking or cycling as modes of travel to and from school and/or work. Environmental context variables included residence, college attendance, and work status. Driving licensure status indicated whether or not participants had an independent driver's license. Poisson regression models, adjusted for potential confounders, were used to test interactions between environmental context and driving licensure. There were significant interactions between environmental context and licensure. Interaction contrasts indicated that participants who did not have a driver's license engaged in more TPA-SW than their licensed counterparts if they were living at home (β=1.10, p<0.001), not attending school (β=0.73, p<0.001), attending a technical school/community college (β=1.13, p<0.001), working 1-30 hours/week (β=0.69, p<0.001), or working 30+hours/week (β=1.12, p<0.001). Among non-workers, those without a license engaged in less TPA-SW than participants with a license (β=-0.22, p=0.05). Among emerging adults in certain environmental contexts, delayed driver licensing may result in more physical activity with the possible tradeoff of less transportation mobility.

Lifestyle correlates of overweight in adults: a hierarchical approach (the SPOTLIGHT project)

BACKGROUND

Obesity-related lifestyle behaviors usually co-exist but few studies have examined their simultaneous relation with body weight. This study aimed to identify the hierarchy of lifestyle-related behaviors associated with being overweight in adults, and to examine subgroups so identified.

METHODS

Data were obtained from a cross-sectional survey conducted across 60 urban neighborhoods in 5 European urban regions between February and September 2014. Data on socio-demographics, physical activity, sedentary behaviors, eating habits, smoking, alcohol consumption, and sleep duration were collected by questionnaire. Participants also reported their weight and height. A recursive partitioning tree approach (CART) was applied to identify both main correlates of overweight and lifestyle subgroups.

RESULTS

In 5295 adults, mean (SD) body mass index (BMI) was 25.2 (4.5) kg/m2, and 46.0 % were overweight (BMI ≥25 kg/m2). CART analysis showed that among all lifestyle-related behaviors examined, the first identified correlate was sitting time while watching television, followed by smoking status. Different combinations of lifestyle-related behaviors (prolonged daily television viewing, former smoking, short sleep, lower vegetable consumption, and lower physical activity) were associated with a higher likelihood of being overweight, revealing 10 subgroups. Members of four subgroups with overweight prevalence >50 % were mainly males, older adults, with lower education, and living in greener neighborhoods with low residential density.

CONCLUSION

Sedentary behavior while watching television was identified as the most important correlate of being overweight. Delineating the hierarchy of correlates provides a better understanding of lifestyle-related behavior combinations which may assist in targeting preventative strategies aimed at tackling obesity.

Associations Between Active Commuting to School, Body Fat, and Mental Well-being: Population-Based, Cross-Sectional Study in China

PURPOSE

Little is known about patterns of active commuting to school (ACS) among school-aged children in China. This study examines mode of transport to school in China and associations with physical and mental well-being among national representative children.

METHODS

Data came from National Puberty Research Collaboration. Commuting mode to school was self-reported and categorized as three categories: walking, cycling, and passive commuting to school. Body mass index, percentage body fat (PBF, measured by skinfold thickness), waist circumference (WC) was measured, and depressive symptoms was assessed by Children's Depression Inventory.

RESULTS

A total of 12,151 girls and 9,445 boys from grade 4 to grade 12 participated in this study. Totally 39.9% of Chinese children walked and 15.9% cycled to school, 44.2% traveled by passive commuting mode. ACS was predictive of lower body mass index, PBF, and WC. Children who commuted via active modes had body mass index, PBF, and WC scores of .167 (95% confidence interval [CI] .274-.060), .566 (95% CI .270-.862), and .724 (95% CI .423-1.025) points lower, respectively, than those who used passive transport. ACS was associated with .855 lower odds of being obese (p < .001) and .907 lower (p < .001) odds of having depressive symptoms compared with children using passive transport.

CONCLUSIONS

ACS is correlated with better physical and mental well-being. Sustainable transport planning aimed at increasing active travel to school among Chinese children and adolescents is in great need.

Associations between active travel and adiposity in rural India and Bangladesh: a cross-sectional study

Background

Data on use and health benefits of active travel in rural low- and middle- income country settings are sparse. We aimed to examine correlates of active travel, and its association with adiposity, in rural India and Bangladesh.

Methods

Cross sectional study of 2,122 adults (≥18 years) sampled in 2011–13 from two rural sites in India (Goa and Chennai) and one in Bangladesh (Matlab). Logistic regression was used to examine whether ≥150 min/week of active travel was associated with socio-demographic indices, smoking, oil/butter consumption, and additional physical activity. Adjusting for these same factors, associations between active travel and BMI, waist circumference and waist-to-hip ratio were examined using linear and logistic regression.

Results

Forty-six percent of the sample achieved recommended levels of physical activity (≥150 min/week) through active travel alone (range: 33.1 % in Matlab to 54.8 % in Goa). This was more frequent among smokers (adjusted odds ratio 1.36, 95 % confidence interval 1.07–1.72; p = 0.011) and those that spent ≥150 min/week in work-based physical activity (OR 1.71, 1.35–2.16; p < 0.001), but less frequent among females than males (OR 0.25, 0.20–0.31; p < 0.001). In fully adjusted analyses, ≥150 min/week of active travel was associated with lower BMI (adjusted coefficient −0.39 kg/m², −0.77 to −0.02; p = 0.037) and a lower likelihood of high waist circumference (OR 0.77, 0.63–0.96; p = 0.018) and high waist-to-hip ratio (OR 0.72, 0.58–0.89; p = 0.002).

Conclusions

Use of active travel for ≥150 min/week was associated with being male, smoking, and higher levels of work-based physical activity. It was associated with lower BMI, and lower risk of a high waist circumference or high waist-to-hip ratio. Promotion of active travel is an important component of strategies to address the growing prevalence of overweight in rural low- and middle- income country settings.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-2411-0) contains supplementary material, which is available to authorized users.

Associations between active travel and weight, blood pressure and diabetes in six middle income countries: a cross-sectional study in older adults

BACKGROUND

There is little published data on the potential health benefits of active travel in low and middle-income countries. This is despite increasing levels of adiposity being linked to increases in physical inactivity and non-communicable diseases. This study will examine: (1) socio-demographic correlates of using active travel (walking or cycling for transport) among older adults in six populous middle-income countries (2) whether use of active travel is associated with adiposity, systolic blood pressure and self-reported diabetes in these countries.

METHODS

Data are from the WHO Study on Global Ageing and Adult Health (SAGE) of China, India, Mexico, Ghana, Russia and South Africa with a total sample size of 40,477. Correlates of active travel (≥150 min/week) were examined using logistic regression. Logistic and linear regression analyses were used to examine health related outcomes according to three groups of active travel use per week.

RESULTS

46.4% of the sample undertook ≥150 min of active travel per week (range South Africa: 21.9% Ghana: 57.8%). In pooled analyses those in wealthier households were less likely to meet this level of active travel (Adjusted Risk Ratio (ARR) 0.77, 95% Confidence Intervals 0.67; 0.88 wealthiest fifth vs. poorest). Older people and women were also less likely to use active travel for ≥150 min per week (ARR 0.71, 0.62; 0.80 those aged 70+ years vs. 18-29 years old, ARR 0.82, 0.74; 0.91 women vs. men). In pooled fully adjusted analyses, high use of active travel was associated with lower risk of overweight (ARR 0.71, 0.59; 0.86), high waist-to-hip ratio (ARR 0.71, 0.61; 0.84) and lower BMI (-0.54 kg/m(2), -0.98;- 0.11). Moderate (31-209 min/week) and high use (≥210 min/week) of active travel was associated with lower waist circumference (-1.52 cm (-2.40; -0.65) and -2.16 cm (3.07; -1.26)), and lower systolic blood pressure (-1.63 mm/Hg (-3.19; -0.06) and -2.33 mm/Hg (-3.98; -0.69)).

CONCLUSIONS

In middle-income countries use of active travel for ≥150 min per week is more common in lower socio-economic groups and appears to confer similar health benefits to those identified in high-income settings. Efforts to increase active travel levels should be integral to strategies to maintain healthy weight and reduce disease burden in these settings.

A longitudinal analysis of the effects of socioeconomic factors, foreign media, and attitude toward appearance on general and central adiposity in Chinese adolescents

This paper explores the longitudinal effects of socioeconomic factors (i.e., parent education and family income level), foreign media, and attitude toward appearance on general and central adiposity among Chinese adolescents.

A longitudinal analysis was performed using data from the China Seven Cities Study, a health promotion and smoking prevention study conducted in seven cities across Mainland China between 2002 and 2005. Participants included 5,020 middle and high school students and their parents. Explanatory variables included foreign media exposure, attitude toward appearance, parent education, and family income. Three-level, random-effect models were used to predict general adiposity (i.e., body mass index) and central adiposity (i.e., waist circumference). The Generalized Estimating Equation approach was utilized to determine the effect of explanatory variables on overweight status.

Among girls, foreign media exposure was significantly negatively associated with general adiposity over time (β = − 0.06, p = 0.01 for middle school girls; β = − 0.06, p = 0.03 for high school girls). Attitude toward appearance was associated with lesser odds of being overweight, particularly among high school girls (OR = 0.86, p < 0.01). Among boys, parental education was significantly positively associated with general adiposity (β = 0.62, p < 0.01 for middle school boys; β = 0.37, p = 0.02 for high school boys) and associated with greater odds of being overweight (OR = 1.55, p < 0.01 for middle school boys; OR = 1.26, p = 0.04 for high school boys). Across all gender and grade levels, family income was significantly negatively associated with central adiposity over time.

Interventions addressing Chinese adolescent overweight/obesity should consider these factors as potential focus areas.

•

Foreign media exposure decreases BMI over time among girls.

•

Girls placing importance on appearance have lesser odds of being overweight.

•

Boys have greater odds of being overweight with high parent education.

•

High family income was negatively associated with central adiposity.

Active transportation and public transportation use to achieve physical activity recommendations? A combined GPS, accelerometer, and mobility survey study

BACKGROUND

Accurate information is lacking on the extent of transportation as a source of physical activity, on the physical activity gains from public transportation use, and on the extent to which population shifts in the use of transportation modes could increase the percentage of people reaching official physical activity recommendations.

METHODS

In 2012-2013, 234 participants of the RECORD GPS Study (French Paris region, median age = 58) wore a portable GPS receiver and an accelerometer for 7 consecutive days and completed a 7-day GPS-based mobility survey (participation rate = 57.1%). Information on transportation modes and accelerometry data aggregated at the trip level [number of steps taken, energy expended, moderate to vigorous physical activity (MVPA), and sedentary time] were available for 7,644 trips. Associations between transportation modes and accelerometer-derived physical activity were estimated at the trip level with multilevel linear models.

RESULTS

Participants spent a median of 1 h 58 min per day in transportation (8.2% of total time). Thirty-eight per-cent of steps taken, 31% of energy expended, and 33% of MVPA over 7 days were attributable to transportation. Walking and biking trips but also public transportation trips with all four transit modes examined were associated with greater steps, MVPA, and energy expenditure when compared to trips by personal motorized vehicle. Two simulated scenarios, implying a shift of approximately 14% and 33% of all motorized trips to public transportation or walking, were associated with a predicted 6 point and 13 point increase in the percentage of participants achieving the current physical activity recommendation.

CONCLUSIONS

Collecting data with GPS receivers, accelerometers, and a GPS-based electronic mobility survey of activities and transportation modes allowed us to investigate relationships between transportation modes and physical activity at the trip level. Our findings suggest that an increase in active transportation participation and public transportation use may have substantial impacts on the percentage of people achieving physical activity recommendations.

Physical growth of children and adolescents in China over the past 35 years

OBJECTIVE

To examine if economic development in China correlates with physical growth among Chinese children and adolescents.

METHODS

The height, body weight and physical activity level of children and adolescents aged 18 years and under, as well as dietary data, were obtained from seven large surveys conducted in China between 1975 and 2010. Chinese economic development indicators were obtained from the World Bank. Trends in body weight, height, economic data and diet were examined. Tests were conducted to check for correlations between height at 17 years of age and three indicators of economic development: gross domestic product, urbanization and infant mortality rate. Regional differences in physical growth were assessed.

FINDINGS

Between 1975 and 2010, the growth of children and adolescents improved in tandem with economic development. The largest increment in height was observed during the period of puberty. Regional inequalities in nutritional status were correlated with disparities in economic development among regions. Over the past two decades, undernutrition declined among children less than 5 years of age, but in 2010 underweight and stunting were still common in poor rural areas. A large increase in obesity was observed in both urban and rural areas, but especially in large cities and, more recently, in small and medium-sized cities and affluent rural areas.

CONCLUSION

The average weight of children and adolescents has been increasing progressively since the 1970s. Current strategies to combat both child undernutrition and obesity need to be improved, especially in poor rural areas.

Is density of neighbourhood restaurants associated with BMI in rural Chinese adults? A longitudinal study from the China Health and Nutrition Survey

OBJECTIVES

The neighbourhood availability of restaurants has been linked to the weight status. However, little is known regarding the relation between access to restaurant and obesity among the Chinese population. This study aims to explore the relationship between neighbourhood restaurant density and body mass index (BMI) in rural China.

DESIGN

A longitudinal study using data from the China Health and Nutrition Survey (CHNS) was conducted. Participants aged 18 and older from the 2004, 2006, 2009 and 2011 CHNS were recruited Separate sex-stratified random intercept-slope growth models of repeated BMI observations were estimated in the study.

SETTING

The data were derived from rural communities in nine provinces in China.

PARTICIPANTS

There were 11 835 male and 12 561 female person-years assessed in this study.

OUTCOMES

The primary outcome of this study was weight status. It is defined as a BMI value, a continuous variable which is calculated by dividing weight (kg) by the square of height (m(2)).

RESULTS

The study indicated that among men an increase of one indoor restaurant in the neighbourhood was associated with a 0.01 kg/m(2) increase in BMI, and an increase of one fixed outdoor food stall was associated with a 0.01 kg/m(2) decrease in BMI, whereas among women, an increase of one indoor restaurant in the neighbourhood was associated with a 0.005 kg/m(2) increase in BMI, and an increase of one fast-food restaurant and one fixed outdoor food stall was associated with a 0.02 and 0.004 kg/m(2) decline in BMI, respectively.

CONCLUSIONS

The density of neighbourhood restaurants was found to be significantly related to BMI in rural China. The results indicated that providing healthy food choices and developing related public health policies are necessary to tackle obesity among rural Chinese adults.

Associations between active travel to work and overweight, hypertension, and diabetes in India: a cross-sectional study

BACKGROUND

Increasing active travel (walking, bicycling, and public transport) is promoted as a key strategy to increase physical activity and reduce the growing burden of noncommunicable diseases (NCDs) globally. Little is known about patterns of active travel or associated cardiovascular health benefits in low- and middle-income countries. This study examines mode and duration of travel to work in rural and urban India and associations between active travel and overweight, hypertension, and diabetes.

METHODS AND FINDINGS

Cross-sectional study of 3,902 participants (1,366 rural, 2,536 urban) in the Indian Migration Study. Associations between mode and duration of active travel and cardiovascular risk factors were assessed using random-effect logistic regression models adjusting for age, sex, caste, standard of living, occupation, factory location, leisure time physical activity, daily fat intake, smoking status, and alcohol use. Rural dwellers were significantly more likely to bicycle (68.3% versus 15.9%; p<0.001) to work than urban dwellers. The prevalence of overweight or obesity was 50.0%, 37.6%, 24.2%, 24.9%; hypertension was 17.7%, 11.8%, 6.5%, 9.8%; and diabetes was 10.8%, 7.4%, 3.8%, 7.3% in participants who travelled to work by private transport, public transport, bicycling, and walking, respectively. In the adjusted analysis, those walking (adjusted risk ratio [ARR] 0.72; 95% CI 0.58-0.88) or bicycling to work (ARR 0.66; 95% CI 0.55-0.77) were significantly less likely to be overweight or obese than those travelling by private transport. Those bicycling to work were significantly less likely to have hypertension (ARR 0.51; 95% CI 0.36-0.71) or diabetes (ARR 0.65; 95% CI 0.44-0.95). There was evidence of a dose-response relationship between duration of bicycling to work and being overweight, having hypertension or diabetes. The main limitation of the study is the cross-sectional design, which limits causal inference for the associations found.

CONCLUSIONS

Walking and bicycling to work was associated with reduced cardiovascular risk in the Indian population. Efforts to increase active travel in urban areas and halt declines in rural areas should be integral to strategies to maintain healthy weight and prevent NCDs in India. Please see later in the article for the Editors' Summary.

Annual motor vehicle travel distance and incident obesity: a prospective cohort study

BACKGROUND

Obesity has become a major health and economic problem with increasing prevalence. Unfortunately, no country can act as public health exemplar for reduction of obesity. The finding of associations between sedentary behaviors and obesity, independent of the level of physical activity, may offer new insights to prevent this burdensome problem.

PURPOSE

To evaluate prospectively the relationship between annual distance traveled by motor vehicles and subsequent incidence of overweight or obesity in a Mediterranean cohort.

METHODS

Data from a prospective cohort study (Seguimiento Universidad de Navarra Project, 1999-2011) with a permanently open recruitment were analyzed. Self-administered questionnaires are mailed every 2 years, collecting information on dietary habits, lifestyle, risk factors, and medical conditions. Annual kilometers traveled by motor vehicles were grouped into three categories (≤10,000; >10,000 to ≤20,000; and >20,000). Multivariate Cox regression analyses were used to assess the risk of overweight or obesity across categories of distance traveled annually.

RESULTS

In all, 9160 participants (58% female, average age=37 years) were followed up for a median of 6.4 years. During 39,175 person-years of follow-up, 1044 (15.3%) normal-weight participants at baseline became overweight or obese. Among participants who did not change their category of annual kilometers traveled during follow-up, an increased risk of overweight or obesity in the highest category of annual kilometers traveled was observed, compared with the lowest one (hazard ratio=1.4, 95% CI=1.1, 1.7).

CONCLUSIONS

This study suggests a potential pernicious effect of the use of motor vehicles on the risk of overweight or obesity.