The levels of cardiovascular disease risk factors among these Northern Colorado children are similar to those nationally, with many of the risk factors trending downward over this 21 year period. Unfortunately, these risk factors are highly associated with overweight and obesity which are not trending downward. Given these children are on average only 10 years old, finding clinically meaningful differences in CVD risk factors by weight status is important when considering future risk among these children [1, 5]. It is also important when we think about primordial and primary prevention; although our data are cross-sectional, our results suggest that focusing on reducing and eliminating overweight and obesity among children by way of focusing on the family may be the best type of intervention.
As noted previously, when comparing the CVD risk factor levels in this population to national data, we found similar values with average total cholesterol ~ 160 mg/dL nationally among children 6–19 years, and ~162 mg/dl among our population;  average national SBP and DBP are ~106 mmHg and ~58 mmHg respectively and ~102 mmHg and 66 mmHg among our population ; average overweight/obesity is ~34 % nationally among 6–19 years olds  which is quite a bit higher than our study where ~ 21 % were overweight/obese. We found similar values in males and females for these variables; similar to the other studies [2, 3, 7].
When considering the trends in risk factors over time, we again found similar results to those nationally, with most risk factors trending toward more favorable values. For example, the National Health and Nutrition Examination Survey (NHANES, 1988–2010) has shown serum lipids among U.S. youth 6–19 years to favorably decline, and HDL-C to increase, similar to our data. Blood pressure showed minor increases during this time period nationally in contrast to a downward trend in our data. Similar to national data, we did not see trends toward decreasing percentages of overweight/obese children [2, 3, 7].
We were also interested in exposures that may be associated with these CVD risk factors including overweight and obesity as well as the prevalence of risk factors among family members. We found overweight and obese children to have significantly higher levels of CVD risk factors than normal weight children. Specifically, obese children had a ~5 % higher total cholesterol, ~18 % lower HDL-C level, ~14 % higher non-HDL-C level, and ~8 % higher SBP and DBP than normal weight children. Such findings are consistent with the literature where Cottrell et al. found similar percent differences in risk by BMI status among 80,000, 10–12 year olds from the Coronary Artery Risk Detection in Appalachian Communities (CARDIAC) project . Interestingly, data from the Bogalusa Heart study showed that being overweight in childhood was associated with adult carotid intima-media thickness, suggesting that long-term exposure to such CVD risk factors can have implications for future coronary artery disease . Our data along with these studies suggest that aiming our efforts at both preventing and treating obesity in children may be one of our most effective means of preventing cardiovascular disease later in life.
We also considered the association of CVD risk factors among family members with risk factors among the children. We found that among children with five to six CVD risk factors (as described in the methods), 56.5 % of the parents/family members reported being overweight compared to children with 0 risk factors, where ~32.2 % reported being overweight. This is not surprising given that parent’s guide the health behaviors and practices of the children [10, 11] and that overweight and obesity were highly correlated with CVD risk factors in our population. When we only considered families reporting an overweight family member, we found 32 % of the children in this group were either overweight or obese; while only 14 % of children were overweight or obese among those families who did not report an overweight family member (data not shown). These findings support the strong association between family CVD risk factors, particularly being overweight and children’s risk factors. Further, these results corroborate a study of 7-year old children from Oulu, Finland (n = 855) where they found childhood obesity was most predicted by mother’s obesity followed by low physical activity and skipping breakfast . Overall, family lifestyles may have a major influence on the future habits of children, including diet, physical activity, and smoking that eventually influence clinical outcomes including hypertension, diabetes mellitus, obesity, and dyslipidemia [1, 10]. If we can educate parents/families about the strong associations between weight status and CVD risk factors; focusing more on the “implications” of weight status, we may find more success in our interventions aimed at preventing and treating overweight and obesity . In non-published data we found parents reported being more willing to try and change unhealthy lifestyle habits if they knew it was negatively impacting their child’s health; further, it has been shown that family interventions succeed over individual level interventions. A study by Epstein et al. found obese children assigned with an obese parent to diet, exercise and behavior management training showed reduced obesity compared to those children not assigned with a parent .
This study has some limitations. Cholesterol levels were determined in the non-fasting state; however, recent evidence supports the use of non-fasting lipid levels. Numerous studies, including a community-based population study, have found fasting time to be minimally associated with lipid levels [15, 16]; we therefore do not believe the use of non-fasting samples altered our data in any meaningful way. This data was collected cross-sectionally over a 21 year time period, therefore, we could not report on individual changes in risk factors over time and we could not determine if overweight or obesity preceded CVD risk levels in children, only that they are associated. Similarly, we do not know that family risk factors preceded the child’s risk factors, only that they are associated. The family risk factor profiles were all self-reported and so there could be some misclassification bias; however this was likely random and would therefore not be expected to influence the associations with the children’s CVD risk factors. This study was conducted in a primarily white population and therefore caution is advised in generalizing these results to other populations. Strengths of this paper include the objective measures of CVD risk markers collected and analyzed over this 21 year period in conjunction with the data obtained on family members.