Abstract
OBJECTIVE: To examine the association of BMI percentile and change in BMI percentile to change in blood pressure (BP) percentile and development of hypertension (HTN). METHODS: This retrospective cohort included 101 606 subjects age 3 to 17 years from 3 health systems across the United States. Height, weight, and BPs were extracted from electronic health records, and BMI and BP percentiles were computed with the appropriate age, gender, and height charts. Mixed linear regression estimated change in BP percentile, and proportional hazards regression was used to estimate risk of incident HTN associated with BMI percentile and change in BMI percentile. RESULTS: The largest increases in BP percentile were observed among children and adolescents who became obese or maintained obesity. Over a median 3.1 years of follow-up, 0.3% of subjects developed HTN. Obese children ages 3 to 11 had twofold increased risk of developing HTN compared with healthy weight children. Obese children and adolescents had a twofold increased risk of developing HTN, and severely obese children had a more than fourfold increased risk. Compared with those who maintained a healthy weight, children and adolescents who became obese or maintained obesity had a more than threefold increased risk of incident HTN. CONCLUSIONS: We observed a strong, statistically significant association between increasing BMI percentile and increases in BP percentile, with risk of incident HTN associated primarily with obesity. The adverse impact of weight gain and obesity in this cohort over a short period underscores the early need for effective strategies for prevention of overweight and obesity.
Generated Summary
This retrospective cohort study investigated the relationship between BMI percentile, change in BMI percentile, and the development of hypertension (HTN) in a large cohort of children and adolescents aged 3 to 17 years. The study utilized electronic health records (EHRs) from three geographically diverse integrated health care delivery systems across the United States. The primary objective was to determine how BMI percentile and changes in BMI percentile are related to changes in blood pressure (BP) percentile and the onset of HTN. The study followed a cohort of 100,606 subjects for a median of 3.1 years. The methodology involved extracting height, weight, and BP data, computing BMI and BP percentiles, and using mixed linear regression and proportional hazards regression to analyze the associations between BMI, changes in BMI, and the risk of developing HTN. The study also examined the influence of weight changes on BP and the subsequent risk of HTN, aiming to provide insights into the early prevention of overweight and obesity through the lens of BP and HTN.
Key Findings & Statistics
- The study population consisted of 100,606 children and adolescents, with 66,991 (65.6%) aged 3 to 11 years and 33,615 (33.4%) aged 12 to 17 years.
- 45% of the study participants were non-Hispanic white.
- The median follow-up duration was 3.1 years.
- At baseline, 16% of the participants were overweight, 2% were obese, and 4% were severely obese.
- Regarding baseline SBP, 92.6% were within the normal range (<90th percentile), 4% were prehypertensive (90th to 95th percentile), and 4% were hypertensive (≥95th percentile).
- A total of 343 (0.3%) subjects newly met the clinical criteria for HTN during the follow-up period, resulting in an incidence rate of 0.15 per person-year.
- Children aged 3 to 11 years who were obese had a significantly greater likelihood of developing HTN (HR = 2.02; 95% CI, 1.28–7.04), and obese adolescents showed a similar risk (HR = 2.20; 95% CI, 1.24–3.91).
- Compared to low healthy weight, children and adolescents who were severely obese were 4.42 (95% CI, 2.77–7.04) and 4.46 (95% CI, 2.39-8.31) times more likely to develop HTN.
- Among children and adolescents with healthy BMI at baseline, 80% and 87%, respectively, maintained their healthy weight status.
- 0.3% and 0.1% of those with healthy BMI at baseline progressed to obese or severely obese categories.
- Of those overweight at baseline, 36% and 52% remained overweight.
- 19% and 13% of those overweight became obese, while 0.7% and 0.1% became severely obese.
- 44% and 34% of those overweight at baseline shifted to a healthy weight.
- Among the obese at baseline, only 5% of the children and 4% of the adolescents decreased to a healthy BMI, with 39% and 31% remaining obese or transitioning to overweight.
- The hazard ratio (HR) for developing HTN was greatest among children and adolescents who stayed obese (HRs = 3.71 and 3.64, respectively).
- Adolescents who transitioned from healthy weight to overweight had an HR of 3.06 (95% CI, 1.42–6.59) for developing HTN, and those who went from overweight to obese had an HR of 5.15 (95% CI, 2.24–11.86).
- Even children and adolescents who transitioned from obese to overweight remained at a higher risk for HTN (HRs = 1.79 and 1.46, respectively).
Other Important Findings
- A statistically significant linear trend of increasing SBP and DBP percentile was observed with increasing BMI category across all age-gender groups.
- Obese and severely obese children and adolescents had the highest mean SBP percentiles, but the means remained within the normal range (between the 58.6th and 60.8th percentiles).
- In both age groups and genders, SBP and DBP percentiles increased significantly when BMI increased from normal to overweight or obese, and from overweight to obese.
- Children and adolescents who decreased from obese to healthy weight or overweight to healthy weight experienced significant changes in SBP and DBP percentiles.
- Children and adolescents whose weight increased to overweight, obese, or severely obese had statistically significant increases in SBP and DBP percentiles.
- There were no statistically significant differences in annual visit rate between BMI change categories.
- The study found a strong association between change in BMI category and change in BP across BMI categories in both age groups and genders.
Limitations Noted in the Document
- The study’s inclusion criteria required that a child have three separate clinic BP measurements during the observation period, leading to potential exclusion of some children and adolescents.
- The criterion of requiring 3 separate visits for an HTN diagnosis might introduce bias, as children with more clinic visits could be identified as hypertensive more often. A sensitivity analysis changing the inclusion criteria to ≥2 visits identified only 8 additional cases of HTN, suggesting that the impact of this criterion was not significant.
- The findings may not be generalizable to other patient populations or care delivery systems due to variations in race and ethnicity.
- The accuracy of BP, height, and weight measurements in routine clinical care could be questioned. However, the study employed trained personnel and data review procedures to minimize inconsistencies.
- The study did not account for comorbid conditions that could influence BP levels, such as diabetes, renal disease, inflammatory diseases, or smoking.
Conclusion
The study underscores a strong association between BMI changes and BP, highlighting obesity, especially severe obesity, as a key risk factor for HTN in young individuals. The data suggests that weight gain and the development of obesity significantly elevate the risk of HTN, underscoring the importance of early intervention strategies. The findings emphasize the need for proactive measures to address overweight and obesity. The study emphasizes the urgent need for effective clinical and public health strategies for preventing overweight and obesity, given the clear link between weight changes and increased BP, which could potentially lead to the early onset of cardiovascular diseases. The study’s large cohort and focus on changes in BMI and its relation to BP provide valuable insights into the early detection and prevention of HTN. The research emphasizes the importance of ongoing monitoring of BP and BMI, and promoting healthy lifestyles from a young age. The study suggests that efforts to maintain a healthy weight, particularly in children and adolescents, could lead to improvements in blood pressure and reduce the risk of HTN. The findings from this study highlight the adverse health implications associated with changes in weight categories, emphasizing the need for initiatives that can help prevent childhood obesity and its related health complications. Overall, the study reinforces the critical need for early and effective strategies to combat obesity and its associated health issues, thereby preventing the early onset of cardiometabolic diseases.