Rural–Urban Differences in Physical Activity, Physical Fitness, and Overweight Prevalence of Children
The authors would like to thank the students, their parents, and teachers for participating in the Physical Activity and Nutrition Among Rural Youth project: Larry Hensley, principal investigator. For further information, contact: Roxane R. Joens-Matre, PhD, Public Health Faculty, Des Moines University, AC #336, 3200 Grand Avenue, Des Moines, IA 50312; e-mail firstname.lastname@example.org.
ABSTRACT: Context:The increasing prevalence of overweight in youth has been well chronicled, but less is known about the unique patterns and risks that may exist in rural and urban environments. A better understanding of possible rural–urban differences in physical activity profiles may facilitate the development of more targeted physical activity interventions. Methods: Participants (1,687 boys; 1,729 girls) were recruited from fourth, fifth, and sixth grade classes in schools from urban areas, small cities, and rural areas. Multilevel modeling analysis was used to examine rural–urban differences in physical activity and prevalence of overweight. Physical activity was assessed by self-report and body mass index was calculated from measured height and weight. Findings: Prevalence of overweight was higher among rural children (25%; P < .001) than children from urban areas (19%) and small cities (17%). Urban children were the least active overall (Cohens' d =−0.4), particularly around lunchtime while at school (d =−0.9 to −1.1). Children from small cities reported the highest levels of physical activity. Conclusions: The results of this study suggest there are rural–urban differences in children's prevalence of overweight and physical activity even within a fairly homogenous Midwestern state.
The increasing prevalence of youth who are overweight is one of the most pressing public health problems facing the country.1 An “obesigenic” environment that limits physical activity has been implicated as a major contributing factor in the obesity epidemic.2–4 Among youth, declines in school physical education time and the percentage of children walking to school have been highlighted as possible contributing factors to the increasing prevalence of overweight.5 Increasing opportunities and promotion of physical activity in youth is critical to reverse the prevalence of obesity.
Broad social ecological approaches to the promotion of physical activity are widely recognized as the most effective methods for altering the complex social and environmental factors that influence this epidemic.6 However, most experts suggest that targeted interventions for specific subpopulations are needed to successfully increase physical activity.7 Thus, examining specific subpopulations within a social ecological approach is clearly needed.
Although the association between physical activity and social factors such as gender and race/ethnicity have been widely examined, geographical factors have received less attention, particularly within the homogenous population of the Midwest. Nationally, adults in rural areas have been shown to have a higher incidence of obesity and physical inactivity than adults in urban settings.8 This may seem counterintuitive based on the belief of the high physical demands of rural life but is reflective of the changing nature of rural life.9 Rural life does not necessarily encompass physically demanding tasks anymore and may be a factor in the higher incidence of obesity in rural areas.
Although data on obesity prevalence and physical activity of rural adults has been fairly consistent, there are fewer studies on rural youth and the results have been more equivocal. One study of Mississippi youth showed 54% of a rural sample were overweight or at risk for being overweight,10 values which are considerably higher than the national youth prevalence of 30% for overweight and at risk for overweight.11 Rural Mississippi youth also reported lower physical activity levels than a comparison national sample, although geographic settings for the national sample were not specified.10 A Midwest study comparing rural youth to a national sample also indicated that rural youth were less active than urban youth.12 In contrast, no differences in physical activity were reported in studies comparing youth of rural and urban residence in North Carolina, although differences were noted in obesity and cardiovascular risk factor profiles.13,14 A study of girls in South Carolina similarly reported no differences in activity levels by geographical setting.15
The inconsistent nature of these studies may be due, in part, to confounding by other variables. A review of research on rural–urban differences concluded that the higher prevalence of obesity in rural areas may be attributed to the lower socioeconomic status (SES) of rural populations.16 The fact that physical inactivity has been similarly associated with low SES in children17 indicates that this is a variable that needs to be considered when examining rural–urban differences.
The Midwest has the largest land mass allocated to agriculture in the United States, but little information is available on the activity patterns or prevalence of obesity of urban and rural youth in this part of the country. The present study employs multilevel modeling analysis18 to examine urbanization influences on physical activity and the prevalence of being overweight in a large sample of elementary school children in the Midwestern state of Iowa. (The Centers for Disease Control and Prevention recommend use of the word “overweight” rather than “obesity” to describe excess weight, to minimize the potential of negative labeling for youth. “Overweight,” therefore, is used in reporting the results of the present study.) Iowa is typically considered to be a rural state although there are areas of urbanization. The use of multilevel modeling accounts for individual school differences; therefore, possible geographic differences are shown more clearly.
Participants The sample included 3,416 Iowa children (1,687 boys; 1,729 girls) from grades 4 (n = 1,243), 5 (n = 1,119), and 6 (n = 1,054). The mean age of the participants was 10.6 ± 0.96 years (range: 8-12 years). Data were obtained from the Physical Activity and Nutrition Among Rural Youth (PANARY) project, a large statewide study aimed at understanding the unique needs of rural youth. A total of 41 elementary schools participated in the project during the 2003-2004 school year and these schools were distributed in 21 (of 99) different counties, representing diverse geographical areas in the state. Although participation rates were not tracked at the time of data collection, mean participation rates of students in the selected schools were calculated to be 64%, based on 2003-2004 certified enrollment statistics.
The level of urbanization was determined by 1993 Rural-Urban Continuum Codes (RUCC), which distinguish metropolitan counties by size and nonmetropolitan counties by degree of urbanization and proximity to metro areas.19 In this study, codes of 0-2 defined large urban areas, a code of 3 defined metropolitan areas identified in this study as “small cities” (population less than 250,000 in the county), and codes of 4-9 defined rural areas. Parental consent was obtained for all participants prior to testing. The Institutional Review Board at Iowa State University approved the instruments and procedures used in the study.
Measure of Body Mass Index Height and weight of the students were measured by trained physical education teachers. Children were attired in light-weight gym clothes without shoes for this assessment. Body mass index (BMI) was calculated from measured height and weight. BMI-for-age percentiles were calculated on the basis of the 2000 Centers for Disease Control and Prevention (CDC) charts. According to definitions set by the CDC, youth with a BMI ≥85th percentile but <95th percentile are considered to be “at risk for overweight.” Youth with BMI above or equal to the 95th percentile are categorized as “overweight.” Youth with a BMI below the 85th percentile are categorized as “normal weight.”
Measure of Physical Activity Physical activity was assessed using the Physical Activity Questionnaire for Children–PAQ-C.20 This instrument assesses a child's self-report of typical level of activity in different settings and different times of the day (eg, physical education class, activity at lunch, activity on the weekend). Each of the nine questions is scored on a 1-5 Likert-type scale and the average is used to represent the activity level of the child. The PAQ-C has been shown to have adequate test-retest reliability (range: r= .75-.82) and reasonable validity (range: r= .45-.53) when compared against objective measures of physical activity.21 Past studies have also supported its use as a measure of physical activity in youth.22 The present study is unique in that differences in the individual items of the PAQ-C were also analyzed to determine possible environmental differences in physical activity opportunities and patterns in the population.
Analysis Descriptive statistics including means and SD were calculated by gender and grade level of participants. Initial results showed no significant differences by grade; therefore, data from all three grades were combined, with age entered as a covariate. Because of the nested nature of the data (individuals within schools), intraclass correlation coefficients (ICC) were computed to determine the degree of school-level clustering. The ICC values were r > .01 for the PAQ-C, indicating that school units accounted for variability of sufficient magnitude in the sample to warrant multilevel modeling.23 Statistical tests were conducted with F values adjusted for clustering. The alpha level was set at 0.05 for these comparisons. Cohen's d effect sizes were reported for the significant differences [d= (Mi− Mj)/SDpooled] to indicate the magnitude of the differences.24
Seventeen percent of the children were from counties classified as urban areas, 54% were from counties classified as small cities, and 30% were from rural areas (nonmetropolitan counties). Ethnicity was not tracked at the individual level, but the overall school-level distributions were similar across the three regions and similar to overall distributions in the state (∼90% white). Ethnicity was not appreciably correlated with physical activity (r=−0.04), VO2 (r=−0.08), BMI (r= .04), or SES (r= .05), although all of the values were statistically significant at P < .05. SES was estimated at the school level by the percentage of students eligible for free or reduced-cost lunches. The percentage of students eligible for free and reduced-cost lunches was highest in rural areas (40%), followed by small cities (24%) and urban areas (18%). SES was positively correlated with the Rural-Urban Continuum Code (r= 0.51; P < .01), indicating that lower SES was associated with rural areas.
Descriptive statistics (using unadjusted means) for physical activity and BMI are provided in Table 1. Table 2 shows the classification of weight (eg, normal weight, at-risk for overweight, overweight) by level of urbanization. The alpha reliability coefficients indicated acceptable internal consistency for the PAQ-C scale (α= 0.72).
Table 1. Comparison of Unadjusted Means ± SD for BMI and Physical Activity by Gender and Level of Urbanization
|Body Mass Index||20.2 ± 4.2 ||19.5 ± 3.9 ||19.7 ± 4.1 ||20.0 ± 6.7 ||21.3 ± 5.5 ||20.7 ± 4.6 |
|Overall PAQ-C*||3.0 ± 0.7||2.8 ± 0.7||3.3 ± 0.7||3.1 ± 0.7||3.2 ± 0.7||3.1 ± 0.7|
|PE class||4.3 ± 0.9||4.2 ± 0.9||4.3 ± 0.8||4.3 ± 0.9||4.1 ± 0.9||3.9 ± 1.1|
|Around lunchtime||1.1 ± 0.4||1.0 ± 0.2||2.5 ± 1.7||2.3 ± 1.6||2.7 ± 1.8||2.3 ± 1.5|
|After school||3.4 ± 1.4||3.3 ± 1.2||3.7 ± 1.4||3.4 ± 1.3||3.5 ± 1.3||3.3 ± 1.3|
|Evening||3.2 ± 1.3||3.1 ± 1.1||3.4 ± 1.2||3.3 ± 1.2||3.4 ± 1.2||3.3 ± 1.2|
|Weekend||3.7 ± 1.2||3.6 ± 1.1||3.6 ± 1.2||3.4 ± 1.2||3.6 ± 1.2||3.5 ± 1.2|
|Screen time||3.8 ± 1.4||3.6 ± 1.3||3.7 ± 1.4||3.4 ± 1.3||3.6 ± 1.5||3.4 ± 1.4|
Table 2. Body Mass Index-for-Age Classifications by Gender and Level of Urbanization
|At-risk for overweight||17.8%||19.5%||21.8%|
Body Mass Index Rural children had a higher mean BMI [F(2,2734) = 12.9, P < .01] than children from small cities or urban areas, but this difference was significant at the 95% CI only for rural boys. The BMI of boys and girls did not differ significantly, and these small gender differences did not vary between geographical areas. Prevalence of overweight was higher among rural children (25%) than children from urban areas (19%, P < .001) and small cities (17%, P < .001). Rural children were 1.47 times more likely to be categorized as overweight than children from small cities.
Physical Activity Urban children were the least active [F(2,3477) = 33.28, P < .01], although effect sizes were small to moderate (d=−0.43). Children from small cities reported a slightly higher PAQ-C than rural children. Boys were more active than girls [F(1,3477) = 25.4, P < .01; d= 0.15] and these gender differences did not vary by location. Table 1 shows the differences in physical activity by gender and level of urbanization.
The largest difference in total physical activity (accounting for 10.8% of the variance) was due to less activity at lunchtime reported by urban children (mean PAQ = 1.0 +/– 0.3) as compared to children from small cities (mean PAQ = 2.4+/–1.6; d=−0.9) and rural areas (mean PAQ = 2.5+/–1.7; d=−1.1). Urban children also reported less activity after school and in the evening than children from small cities and rural areas (significant differences at 95% CI only for urban boys in the evening), but there were no differences in physical activity during the weekend. Rural children reported the least activity during physical education class, although the effect size was small (d=−0.22). Table 1 shows the differences in physical activity at specific times of the day.
This is the first known study to examine levels of BMI and physical activity by level of urbanization in a large sample of Midwest children. The study extends previous research by examining an under-studied region of the country and by utilizing multilevel modeling techniques. The results of this study suggest that there are differences in children's physical activity and prevalence of overweight by level of urbanization, even within a fairly homogenous Midwestern state. Mean physical activity levels were above the midpoint of the scale, but were similar to those shown in a previous study of suburban elementary school-age children.25 In the present study, we found that children from rural areas and small cities were more active than urban children, although the differences were small to moderate.
Previous inconsistencies in findings related to geographic differences in physical activity may be explained by differences in the samples and measures. In the studies reporting lower physical activity levels among rural youth,10,12 comparison groups were not actually measured; rather, conclusions were drawn by extrapolation from previously reported data. Studies directly comparing rural and urban children of the same region at the same time did not show differences in physical activity.13,14 In addition, low family SES (which is prevalent in rural areas) has been associated with lower levels of activity.17 The rural youth in the present study were from lower SES families (40% of the students were eligible for free or reduced-cost lunches [eg, household income < 185% of poverty level or $14,000 for a family of three]) than the urban youth (18% of the students were eligible for free or reduced-cost lunches), but the rural youth were more active. The higher prevalence of lower SES among rural Mississippi youth12 (76% were eligible for free or reduced cost lunches) may explain the different results observed in that study.
An advantage of the present study is that differences in time and location of physical activity were explored by examining individual items on the PAQ-C. Children from small cities reported a slightly greater frequency of activity during physical education time and after school compared to urban and rural children, and this likely contributed to their higher overall level of physical activity. The greatest difference in physical activity among urban children as compared to children from small cities and rural areas was less activity around lunchtime while at school. Physical activity levels were similar for children from all locations on the weekends. Consistent with results reported for other regions of the country, gender disparities were apparent as girls were less active than boys at all ages and in all locations. The smaller difference between girls and boys in the urban sample may have been due to a floor effect, in that the scores were generally low for this group.
The higher prevalence of overweight among rural children (25%) was consistent with results found in other regions of the country.11–13 All three groups showed a higher prevalence of being overweight than the national average of 16% for this age group.11 Overall prevalence for overweight and at risk for overweight was 40%, and this is considerably higher than the national average of 30% for similarly aged children11 and higher than the 25.5% for Iowa youth reported in the 2003 National Children's Health Survey. However, both the national and state averages for the prevalence of overweight were based on parent-reported height and weight rather than measured height and weight, which may explain the discrepancy.
Children who are overweight often have high blood pressure and high cholesterol and are more likely to become overweight adults.26,27 Recent evidence has shown that physical activity may moderate health implications of overweight and this appears to be evident for youth as well. McMurray et al,14 utilizing statistical techniques to adjust for clustering, found that rural children had higher levels of obesity, but not lower levels of physical activity or increased number of risk factors such as total cholesterol and blood pressure. Those results suggested increased physical activity provided a protective effect for overweight youth.
The interactions among physical activity and being overweight are clearly complex. Adding to the complexity are conflicting data regarding the influence that level of urbanization may have on these outcomes. The results of this study suggest modest but significant differences in physical activity and overweight by levels of urbanization in a large sample of elementary school children. However, there are also limitations in the study that should be considered when interpreting the results.
At first glance, the results may appear contradictory given that rural children had higher levels of physical activity than urban children, yet had a higher prevalence of being overweight. Maturity may have influenced height and weight (and subsequent BMI-for-age), and this was not assessed in the present study. Furthermore, overweight is a combination of energy expenditure (including physical activity) and energy intake, and the present study did not address dietary habits, which would have allowed for further exploration of this issue. Second, the scope of the study necessitated the use of a self-report measure of physical activity. The use of accelerometry-based activity monitors would have provided a more objective measure of physical activity but was outside the scope of the study.
Although an objective measure of physical activity may have allowed a determination of whether children were meeting established physical activity guidelines, the factorial nature of the PAQ-C instrument provided some unique advantages. The main advantage was that times and settings were included in the survey that helped explain rural and urban differences between overall activity levels in our sample. Providing physical activity opportunities around lunchtime may be an effective strategy for increasing the physical activity of urban children, whereas increasing physical activity during physical education time and after school may be more important for rural children.
The American Academy of Pediatrics issued a landmark policy statement encouraging parents, pediatric health care providers, and public health officials to advocate for increased physical activity for children and teenagers at home, school, and in the community as a major thrust to combat obesity.28 Interventions need to be uniquely tailored to the ecological settings of each subpopulation. Knowledge of differences in rural and urban areas of the Midwest may help expedite those processes. A socioecological framework involving children, families, schools, and their communities would help to implement programming to address the unique needs of these populations.