The influence of maternal body mass index and physical activity on select cardiovascular risk factors of preadolescent Hispanic children

Introduction

Physical inactivity, elevated blood pressure (BP), and overweight and obesity track from childhood to adulthood (McGill, McMahan & Gidding, 2008; Napoli et al., 2006), and increase the risk of cardiovascular diseases such as heart disease and stroke (Mozaffarian et al., 2016). According to the 2008 Physical Activity Guidelines for Americans (U.S. Department of Health and Human Services, 2008), children should engage in at least one hour of physical activity (PA) per day, including at least three days of moderate-to-vigorous intensity aerobic activity. Adequate PA in childhood can prevent obesity and elevated blood pressure (Expert Panel on Integrated Guidelines for Cardiovascular Health and Risk Reduction in Children and Adolescents, 2011). Despite evidence of the cardiovascular benefits of adequate PA and the detrimental effects of a sedentary lifestyle, a significant number of U.S children and adolescents do not meet national recommendations. Per the 2013 Youth Risk Behavior Survey (Kann et al., 2014), 15.2% of high school students nationwide did not meet the recommendation of at least 60 min of PA in the past week; 41.3% spent three or more hours playing computer or video games un-related to school work; and 32.5% spent three or more hours watching television per day. Only 27.1% of high school students nationwide met the PA guidelines. Of students in kindergarten through the 12th grade nationwide, only 29.4% attended structured daily physical education classes in school (Kann et al., 2012).

Hypertension in children is defined as average systolic (SBP) and/or diastolic (DBP) blood pressure higher than or equal to the 95th percentile for sex, age, and height on three or more repeated measurements (National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents, 2004). Elevated BP, or prehypertension, refers to average SBP or DBP higher than or equal to the 90th percentile, but less than the 95th percentile. Although from 2003–2004 to 2011–2012, the prevalence of elevated BP among 8–17-year-old U.S children decreased from 3.1% to 1.6%, the prevalence of elevated BP was 11.5% for Hispanic children versus 9.4% for non-Hispanic White children in 2011–2012 (Kit et al., 2015). Further, about eighteen percent (17.7%) of children 12-to-19 years old have either poor or intermediate scores on the American Heart Association’s BP metric of cardiovascular health (Mozaffarian et al., 2016). Routine measurement of BP during health care visits is recommended for children three or more years old (Chobanian et al., 2003; Expert Panel on Integrated Guidelines for Cardiovascular Health and Risk Reduction in Children and Adolescents, 2011).

Overweight and obesity remain a major public health problem. Childhood overweight and obesity prevalence rates are high across all racial groups; however, Hispanic children experience higher prevalence of obesity (Falkner & Cossrow, 2014; Kit et al., 2015; Nguyen, Kit & Carroll, 2015) as compared to their non-Hispanic White peers. Hispanic children are also more likely to experience earlier onset of obesity and be severely obese (Mozaffarian et al., 2016) as compared to their non-Hispanic White peers. From 2003–2004 to 2013–2014, the prevalence of obesity among 2–19-year-old U.S children decreased slightly from 17.1% to 16.9%, among 2–19-year-old Mexican American females, it increased from 16.1% to 24.2%, and among 2–19-year-old Mexican American males, it decreased from 22.0% to 19.5% (Cheryl, Carroll & Ogden, 2016). Recommended strategies to prevent obesity include programs to increase PA in the community, increase consumption of fruits and vegetables, environmental approaches to improve transportation and use of land, as well as early care and education at schools (Centers for Disease and Prevention, 2018).

A positive energy balance resulting from a set of risk factors including poor diet, physical inactivity, genes, aging and ethnicity underlie the development of overweight and obesity (Kelly et al., 2013). A similar set of risk factors including obesity, high dietary salt intake, male gender, older age, and ethnicity, drive the development of hypertension in preadolescents (Kelly et al., 2013). In addition to these established risk factors, many studies (Fuemmeler, Anderson & Mâsse, 2011; Ruiz et al., 2011; Whitaker et al., 1997) have found an association between maternal PA and body mass index (BMI), and obesity and hypertension in older children (Durand et al., 2011; Gordon-Larsen et al., 2006; Rosendranz & Dzewaltowski, 2011; Sallis et al., 2009a; Sallis et al., 2009b; Van Den Berg et al., 2013). However, no study has examined the influence of mother’s PA or BMI on Hispanic preadolescents’ BMI, PA and BP.

Therefore, this study tests two related hypotheses: First, mothers who self-report to be less physically active are less likely to self-report that their preadolescent children are physically active, and that their preadolescent children are more likely to self-report as having more screen time. Second, an increased maternal weight is associated with increased preadolescent weight and BP in Hispanic children. It is important to understand the relation between the maternal and child health characteristics among Hispanics in order to inform the development of public health interventions for the large and growing Hispanic community in Tennessee.

Materials & Methods

Results

All mothers and children in the study identified themselves as Hispanic. The mean age of the preadolescents was 6.36 years (SD = 2.75) and half were female (Table 1). Children subjects were identified as 76.3% Mexican-American, and 23.7% as of other Hispanic origin (Puerto Rican, Guatemalan, Ecuadorian and Columbian). About eighty nine percent (88.9%) of mothers had no education beyond high school or the equivalent of high school (Table 1).

About a third (31.4%) of preadolescents had elevated BP, and about 4 out of 10 (40.7%) were overweight or obese. About a fifth (22.0%) of preadolescents spent over two hours per day watching TV or videos, and just over a quarter (26.3%) engaged in less than three days of sixty or more minutes of vigorous PA per week (Table 1).

Two-to-five-year-old preadolescents had a higher prevalence of elevated BP compared to 6-to-10-year-olds (45.7% vs. 22.2%, p = 0.007) (Table 1). Likewise, preadolescents whose mothers did not engage in moderate PA tended to have a higher prevalence of elevated BP (38.7% vs. 23.2%, p = 0.07) (Table 2); and higher prevalence of engaging in less than three days of at least 60 min of vigorous PA per week, (33.9% vs. 19.4%, p = 0.072) (Table 2), than preadolescents whose mothers engaged in moderate PA. Preadolescents whose mothers did not engage in moderate PA tended to have a higher prevalence of being overweight/obese than preadolescents whose mothers engaged in moderate PA, (46.8% vs. 33.9%, p = 0.08). Table 3 shows bivariate associations between preadolescent’s PA, screen time, BP and BMI. Preadolescents’ BMI and BP were significantly associated (p = 0.046).

In adjusted multiple logistic regression, preadolescents of obese mothers were 6.47 times more likely than preadolescents of mothers with normal BMI to engage in less than three days of at least 60 min of vigorous PA per week (95% CI [1.61–26.0]) (Table 4). Preadolescents whose mothers did not engage in moderate PA were 2.92 times more likely to engage in less than three days of at least 60 min of vigorous PA per week (95% CI [1.18–7.24]); and 2.5 times more likely to have elevated BP (95% CI [1.02–4.53]) than preadolescents whose mothers engaged in moderate PA (Table 4).

Discussion

In this study, we found that about four out of every ten preadolescents were overweight or obese (40.7%), and about three out of every ten had elevated BP (31.4%). The study sample’s prevalence of being overweight/obese is similar to national estimates for Hispanic children (Ogden et al., 2014). Estimates of the prevalence of elevated BP in children are few and difficult to compare. In a large cohort study of 3-to-18-year-old children presenting for well-child care, Hansen, Gunn & Kaelbar (2007) determined the prevalence of elevated BP to be 7.0%. A study by Ma, Zhang & Xi (2016) using NHANES 2013–2014 data reported the prevalence of elevated BP in 8-to-17-year-olds to be 7.0%. Kit et al. (2015) also using NHANES data estimated the prevalence of elevated BP in 8-to-17-year-old children to be 11.0% in 2011–2012. The prevalence of elevated BP in this study exceeds estimates from these previous studies. One explanation is the low socioeconomic status of participants. About 89% of mothers had only a high school education or less. Low socioeconomic status is associated with significantly higher obesity and hypertension (Brummett et al., 2011; Van Den Berg et al., 2013).

This study also found that preadolescents of obese mothers were 6.47 times more likely than preadolescents of mothers with normal BMI to engage in less than three days of at least 60 min of vigorous PA per week; and preadolescents whose mothers did not engage in moderate PA were 2.92 times more likely to engage in less than three days of at least sixty minutes of vigorous PA than preadolescents whose mothers engaged in moderate PA. Our findings comport with previous studies which have found strong mother-child correlations in PA and a strong association between maternal obesity and child PA. In a study of 3-to-5-year-old Hispanic preadolescents and their mothers at a local community center in Nashville, TN, Ruiz et al. (2011) observed strong mother-child correlation in sedentary behavior and moderate PA; Fuemmeler, Anderson, and Masse (2011) found a high correlation of moderate-to-vigorous PA (MVPA) between mothers and their preadolescents. Rosendranz & Dzewaltowski (2011) found that mother-child shared PA was negatively associated with child BMI percentile, and that maternal BMI was positively correlated with child BMI. The same study evaluated the effects of PA-related-parenting behaviors such as encouragement, transporting the child for PA and watching the child do PA. Of all PA-related-parenting behaviors, PA encouragement had the strongest correlation with child PA.

We also found that preadolescents whose mothers did not engage in moderate PA were 2.5 times more likely to have elevated BP than preadolescents whose mothers engaged in moderate PA. Physical inactivity and overweight are risk factors for elevated BP in preadolescents (Ewald & Haldeman, 2016; Gopinath et al., 2014; Leary et al., 2008). However, after controlling for child PA, and BMI, preadolescents whose mothers did not engage in moderate PA remained significantly more likely to have elevated BP than preadolescents whose mothers engaged in moderate PA. To the best of our knowledge, this is the first study to report a significant association between maternal PA and child BP in Hispanic preadolescents, independent of child’s BMI and PA.

This study has some limitations. The sample size was relatively small; hence the study may have lacked power to reach significance for some of the associations. Second, being a cross-sectional study of predominantly Mexican-Americans, our findings may not be generalizable to all Hispanic preadolescents and do not indicate causality. Longitudinal studies are needed for further investigating the correlation between maternal and preadolescent factors examined in this study. Third, our inability to control for diet may potentially confound our findings. However, these weaknesses should be weighed against the strengths of this study. To the best of our knowledge, this is the first study which has assessed the prevalence and sociodemographic correlates of elevated BP in Hispanic preadolescents in Tennessee.

Conclusions

The prevalence of overweight or obesity and elevated BP among Hispanic preadolescent subjects, especially in 2-to-5-year-olds was higher than expected based on estimates from national studies (Kit et al., 2015; Ma, Zhang & Xi, 2016). Low maternal PA was associated with elevated BP and lower PA in preadolescents; likewise, maternal obesity was associated with lower PA in preadolescents. Our findings suggest the need for public health interventions that would encourage mothers to increase physical activity and improve weight control as a means for reducing obesity and hypertension in Hispanic preadolescents.