An observational study of the Kaiser Permanente Northern California (KPNC) BMI coding distributions was conducted to ascertain the trends in overweight and obesity prevalence among KPNC members aged 2–19 between the periods of 2003–2005 and 2009-2010. A decrease in the prevalence of overweight (−11.1% change) and obesity (−3.6% change) and an increase in the prevalence of healthy weight (+2.7% change) were demonstrated. Children aged 2–5 had the greatest improvement in obesity prevalence (−11.5% change). Adolescents aged 12–19 were the only age group to not show a decrease in obesity prevalence. Of the racial and ethnic groups, Hispanics/Latinos had the highest prevalence of obesity across all age groups. The KPNC prevalence of overweight and obesity compares favorably to external benchmarks, although differences in methodologies limit our ability to draw conclusions. Physician counseling as well as weight management programs and sociodemographic factors may have contributed to the overall improvements in BMI in the KPNC population. Physician training, practice tools, automated BMI reminders and performance feedback improved the frequency and quality of physician counseling. BMI screening and counseling at urgent visits, in addition to well-child care visits, increased the reach and dose of physician counseling.
From 1970 to 2000, the number of obese children in the USA tripled. From 2000 to 2010, no statistically significant linear trends in body mass index (BMI) were detected; however, 30.4% of children and adolescents aged 2 through 19 years were overweight or obese in 2009-2010 [
Although some studies suggest that child obesity is less prevalent in California than in other states [
In 2001, KPNC began a multifaceted initiative to address childhood obesity in Northern California. This initiative had 3 components: medical office visit interventions, weight management interventions, and environmental changes (Figure Identify existing patterns amongst age and racial/ethnic groups. Assess progress towards reversing the childhood obesity epidemic. Identify areas or population segments to target for future interventions.
KPNC’s approach to childhood obesity.
KPNC is an integrated, prepaid, nonprofit health care delivery system in Northern California. KPNC has 3.3 million members, which represents 35–40% of the insured market in the Northern California catchment area. The median income of the membership parallels that of the general population, with fewer members at both the high and low extremes [
In 2003–2005, BMI was captured primarily at well-child visits and coded in the EHR, whereas in 2009-2010, BMI was captured at well-child and urgent care visits and coded in the EHR. Young adults aged 18 and 19 were included to be consistent with the National Health and Nutrition Examination Survey (NHANES) analysis [
To compare distributions of BMI categories between the time periods, races, and/or age groups, it was necessary to adjust the distributions for sample comparability. For example, differences in the prevalence rates of obesity at two different times could be due to the programs implemented between the two times, temporal trends in the community, or differences in the characteristics of the sample of people at the two time points. To account for differences in the characteristics of the samples, prevalence rates were directly adjusted for age, gender, and race/ethnicity [
To compare the rates of obesity and overweight within KPNC to those in the surrounding regions, we used prevalence rates amongst 5th, 7th, and 9th graders from the counties of Alameda, Contra Costa, Fresno, Madera, Marin, Merced, Sacramento, San Francisco, San Joaquin, San Mateo, Santa Clara, Solano, Sonoma, Stanislaus, and Yolo in 2005 and 2010 [
To test for statistically significant differences over time (2003–2005 period versus 2009-2010 period), a set of 4 logistic regression models were fit, one for each BMI category. In each model, the independent variables were age, sex, race/ethnicity, time (2003–2005 versus 2009-2010), and the interactions between time and each of the other variables. When an interaction was statistically significant (
This study was done as a quality improvement effort to inform KPNC’s approach to reduce the prevalence of overweight and obesity in its pediatric population and therefore did not require IRB review.
The samples from the 2 study periods were similar with regard to age and sex distribution (Table
Age, sex, and race/ethnicity distributions at each time period.
2003–2005 | 2009-2010 | |
---|---|---|
|
|
|
Ages, years | ||
02–05 | 85,804 (33.8%) | 137,479 (32.2%) |
06–11 | 82,464 (32.5%) | 140,815 (33.0%) |
12–19 | 85,739 (33.7%) | 148,383 (34.8%) |
Sex | ||
Male | 128,598 (50.6%) | 218,249 (51.1%) |
Female | 125,404 (49.4%) | 208,423 (48.9%) |
Race/ethnicity | ||
Asian | 34,413 (13.6%) | 63,947 (15.0%) |
Black | 23,179 (9.1%) | 34,175 (8.0%) |
Hispanic/Latino | 25,959 (10.2%) | 55,977 (13.1%) |
White | 98,449 (38.8%) | 153,714 (36.3%) |
Other | 21,660 (8.5%) | 40,918 (9.6%) |
Unknown | 50,342 (19.8%) | 76,941 (18.0%) |
| ||
Total | 254,007 | 426,677 |
We compared the directly adjusted BMI category prevalence rates for the 2 study periods (Table
Directly adjusted BMI category distribution by weight category, age, and time.
Underweight (<5th percentile) | Healthy weight (5–84.9th percentile) | Overweight (85–94.9th percentile) | Obese (≥95th percentile) | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
2003–2005a | 2009-2010a | Percentage point difference | Percent changeb | 2003–2005a | 2009-2010a | Percentage point difference | Percent changeb | 2003–2005a | 2009-2010a | Percentage point difference | Percent changeb | 2003–2005a | 2009-2010a | Percentage point difference | Percent changeb | |
Ages 02–05 |
2.2% |
2.9% |
|
|
75.5% |
77.3% |
|
|
11.0% |
9.7% |
|
|
11.3% |
10.0% |
|
|
Ages 06–11 |
1.5% |
1.8% |
|
|
62.3% |
65.1% |
|
|
15.9% |
13.8% |
|
|
20.3% |
19.3% |
|
|
Ages 12–19 |
1.5% |
1.6% |
+0.1 | +6.7% | 63.2% |
64.3% |
|
|
16.4% |
14.8% |
|
|
19.0% |
19.3% |
+0.3 | 1.6% |
All |
1.7% |
2.1% |
|
|
67.0% |
68.8% |
|
|
14.4% |
12.8% |
|
|
16.9% |
16.3% |
|
|
bPercent change = percentage point difference/percent weight category in 2003–2005.
Bold indicate statistically significant (
BMI category prevalence rates were directly adjusted for each combination of age and race/ethnicity separately for the 2 time periods (Table
Directly adjusted BMI category distribution by weight category, age, race/ethnicity, and time.
Percent overweight | Percent obese | |||||
---|---|---|---|---|---|---|
BMI 85–94.9th percentile | BMI ≥ 95th percentile | |||||
2003–2005a | 2009-2010a | OR (95% CI) | 2003–2005a | 2009-2010a | OR (95% CI) | |
Asian | ||||||
Ages 02–05 | 8.6% |
7.7% |
|
9.6% |
8.1% |
|
Ages 06–11 | 15.0% |
12.8% |
|
17.3% |
15.3% |
|
Ages 12–19 | 15.0% |
13.7% |
|
14.1% |
13.8% |
1.00 (0.94, 1.08) |
Black | ||||||
Ages 02–05 | 12.5% |
10.5% |
|
13.0% |
12.2% |
1.08 (0.98, 1.18) |
Ages 06–11 | 16.4% |
14.6% |
|
24.2% |
24.4% |
0.99 (0.93, 1.06) |
Ages 12–19 | 17.6% |
16.2% |
|
24.4% |
25.1% |
0.96 (0.90, 1.03) |
Hispanic/Latino | ||||||
Ages 02–05 | 13.6% |
11.9% |
|
16.7% |
16.0% |
1.05 (0.97, 1.13) |
Ages 06–11 | 18.4% |
15.4% |
|
28.1% |
29.0% |
0.95 (0.90, 1.01) |
Ages 12–19 | 18.3% |
17.0% |
|
25.5% |
26.3% |
0.95 (0.90, 1.01) |
White | ||||||
Ages 02–05 | 10.8% |
9.4% |
|
8.8% |
7.7% |
|
Ages 06–11 | 15.2% |
13.3% |
|
16.5% |
14.9% |
|
Ages 12–19 | 15.4% |
14.1% |
|
15.5% |
15.8% |
0.97 (0.94, 1.01) |
Other | ||||||
Ages 02–05 | 12.1% |
10.9% |
|
15.0% |
14.1% |
|
Ages 06–11 | 17.1% |
14.6% |
|
25.1% |
25.0% |
1.01 (0.94, 1.08) |
Ages 12–19 | 18.3% |
15.4% |
|
26.4% |
26.2% |
1.00 (0.93, 1.08) |
Unknown | ||||||
Ages 02–05 | 11.0% |
9.8% |
|
12.1% |
10.1% |
|
Ages 06–11 | 15.7% |
13.8% |
|
20.2% |
18.8% |
|
Ages 12–19 | 16.4% |
14.5% |
|
19.5% |
19.6% |
1.00 (0.95, 1.05) |
Bold indicate statistically significant (
All age groups and races showed a statistically significant decrease (OR > 1) in overweight prevalence. Asians, whites, and unknown races aged 2–11 and other races aged 2–5 showed a statistically significant decrease (OR > 1) in obesity prevalence.
In 2009-2010, childhood overweight and obesity prevalence rates in KPNC were lower than national prevalence rates for children aged 2–19 [
Overweight and obesity in children aged 2–19, in KPNC and NHANES.
NHANES 2009-2010a | KPNC 2009-2010 | |
---|---|---|
Overweight and obese (BMI ≥ 85th percentile) | 31.8% | 29.2% |
Obese |
16.9% | 16.4% |
Obesity is more prevalent in KPNC Hispanics and Latinos aged 2–19 than it is in a national cohort [
Comparison of obesity in children aged 2–19 years in the NHANES and KPNC populations in 2009-2010, stratified by race and gender.
NHANES PEDIATRIC BMI ≥ 95th |
KPNC PEDIATRIC BMI ≥ 95th | |
---|---|---|
Both sexes | ||
White | 14.0% | 12.8% |
Black | 24.3% | 21.0% |
Hispanic/Latinos | 21.2% | 24.6% |
Male | ||
White | 16.1% | 13.8% |
Black | 24.3% | 19.4% |
Hispanic/Latinos | 23.4% | 27.1% |
Females | ||
White | 11.7% | 11.6% |
Black | 24.3% | 22.7% |
Hispanic/Latinos | 18.9% | 22.1% |
The overall overweight and obesity prevalence rates in KPNC for ages 6–19 years compare favorably with the overweight and obesity prevalence rates for school-age children in the counties served by KPNC [
KPNC counties versus KPNC for childhood and adolescent overweight and obesity in 2005 and 2010.
Year | KPNC countiesa | KPNCb | |
---|---|---|---|
Overweight and obese | 2005 | 36.2% | 35.5% |
2010 | 36.5% | 33.8% | |
Percent changec | +1% | −4.8% |
bThe KPNC sample consists of ages 6–19 years in 2003–2005 and 2009-2010.
cPercent change = percentage point difference/percent overweight and obese in 2005 or 2003–2005.
In the pediatric population of KPNC, obesity and overweight decreased between 2003 and 2010, in contrast to comparator populations in the same geographic location and nationwide. Although our datasets captured only those members who came to a KPNC facility for a visit during the time periods 2003–2005 and 2009-2010, the sample sizes (
Improvements in overweight and obesity among KPNC members may be attributable to sociodemographic differences and/or differences in the clinical care received by KPNC members versus nonmembers. The KPNC adult membership does not significantly differ from the adult population of Northern California with regard to age, sex, or race/ethnicity. However, compared to nonmembers in Northern California, the KPNC adult membership does have significantly lower percentages of men and women with household incomes <200% above the federal poverty line, with incomes of ≤$25,000, and who have not graduated from high school [
KPNC members may have received clinical care that nonmembers did not receive. From 2002 to 2004, training was provided for all KPNC pediatricians and family practitioners to measure BMI and provide family-centered nutrition and physical activity counseling at well-child care visits (Figure
KPNC strategies to address childhood obesity.
From 2002 to 2006, KPNC tripled the number of facilities offering weight management programs for families. Self-care materials, web-based programs, and single-session weight management programs were offered in all service areas at no additional cost to members. Multisession weight management programs were also offered in the clinic setting and varied in intensity from 2 to 20 sessions. These programs were led by health educators and focused on family health behavior change. Many of these programs were evaluated, with most programs demonstrating improvements in health behaviors and multisession programs yielding modest improvements in weight. Many weight management programs for families have produced modest improvements in BMI, with more intensive programs yielding greater improvements [
Pediatricians and family practitioners received training and tools to implement the “Expert Committee Recommendations Regarding the Prevention, Assessment, and Treatment of Child and Adolescent Overweight and Obesity” in 2007–2009 [
In 2009, an EHR was fully implemented and a reminder system was developed that provided all members and providers with an annual BMI screening reminder that members could view on the visit receipt at an office visit and online. Personalized BMI information and education were developed for the After Visit Summary, a printed summary of the visit provided to patients. The use of the EHR to facilitate BMI screening and counseling was demonstrated in a study from Kaiser Permanente Southern California (KPSC) [
Beginning in 2009, providers were encouraged to measure BMI and provide counseling annually at urgent care visits in addition to well-child visits. Clinics were provided quarterly feedback on BMI screening and counseling performance. The addition of BMI screening at urgent visits increased BMI data capture, provided counseling for patients who did not have a well-child care visit, and increased the likelihood that a patient would receive more than one counseling session during the calendar year. Since Medicaid-eligible children are less likely to be compliant with well-child care, more high risk children had BMI screening and received counseling [
Improvement in the prevalence of obesity among KPNC members 2–5 years is encouraging and mirrors improvements in obesity prevalence among low-income preschool-aged children [
Findings from this observational study highlight the strides that KPNC has made in addressing obesity among children and adolescents in its member population. Although weight management programs and sociodemographic factors may have contributed to the overall improvements in BMI in the KPNC population, the contribution was likely to be small. Most of the improvements were likely attributable to physician counseling. Physician training, practice tools, automated BMI reminders, and performance feedback improved the frequency and quality of physician counseling. BMI screening and counseling at urgent visits, in addition to well-child care visits, increased the reach and dose of physician counseling.
These findings have also shed light on the varied response to the intervention. Understanding this variation will be key to quality improvement and will inform the development of strategies and interventions to effectively target groups at risk and to decrease obesity prevalence rates among KPNC’s pediatric population. Two populations that will need further intervention and research are obese adolescents and obese Hispanics/Latinos aged 6–19.