TABLE 2.
Cumulative Incidence Proportion of Obesity From Kindergarten Through Fifth Grade Across Sociodemographic Groups and Risk Ratios Comparing the US 1998 and 2010 Kindergarten Cohorts
| 1998 Kindergarten Cohort | 2010 Kindergarten Cohort | RR for Obesity, 2010 vs 1998 | ||||
|---|---|---|---|---|---|---|
| Estimate | 95% CI | Estimate | 95% CI | Estimate | 95% CI | |
| Overall | 15.5% | 14.1%–16.9% | 16.2% | 15.0%–17.3% | 1.04 | 1.03–1.05 |
| Baseline BMI status | ||||||
| Normal in kindergarten | 9.8% | 8.7%–11.0% | 9.8% | 8.7%–10.9% | 0.99 | 0.98–1.00 |
| Overweight in kindergarten | 42.9% | 38.0%–47.9% | 44.3% | 41.3%–47.3% | 1.03 | 1.00–1.06 |
| Sex | ||||||
| Males | 16.2% | 14.2%–18.3% | 17.7% | 16.1%–19.4% | 1.09 | 1.08–1.11 |
| Females | 14.8% | 12.8%–16.8% | 14.5% | 13.2%–15.9% | 0.98 | 0.97–1.00 |
| Race | ||||||
| White, non-Hispanic | 13.7% | 12.0%–15.4% | 13.6% | 12.3%–14.9% | 0.99 | 0.98–1.00 |
| Black, non-Hispanic | 17.3% | 13.3%–21.3% | 22.4% | 18.2%–26.7% | 1.29 | 1.25–1.34 |
| Hispanic | 19.9% | 16.1%–23.8% | 19.9% | 17.6%–22.1% | 1.00 | 0.97–1.02 |
| Other race groups | 16.1% | 11.7%–20.5% | 13.4% | 10.1%–16.7% | 0.84 | 0.80–0.87 |
| Socioeconomic status | ||||||
| Quartile 1 (lowest) | 17.7% | 14.6%–20.8% | 20.3% | 18.0%–22.6% | 1.15 | 1.12–1.17 |
| Quartile 2 | 18.1% | 15.3%–21.0% | 18.6% | 16.1%–21.1% | 1.03 | 1.00–1.05 |
| Quartile 3 | 16.0% | 12.7%–19.2% | 14.7% | 12.6%–16.8% | 0.92 | 0.90–0.94 |
| Quartile 4 (highest) | 10.3% | 7.8%–12.8% | 11.9% | 10.2%–13.6% | 1.15 | 1.14–1.17 |
| Urbanicity | ||||||
| City | 16.6% | 14.5%–18.6% | 17.3% | 15.5%–19.3% | 1.05 | 1.02–1.07 |
| Urban fringe/large town | 14.5% | 12.5% –16.5% | 16.3% | 14.1%–18.5% | 1.13 | 1.11–1.15 |
| Small town/rural | 15.7% | 11.7%–19.8% | 16.3% | 14.5%–18.0% | 1.03 | 1.02–1.05 |
| Birth weight | ||||||
| Low birth weight | 11.6% | 6.9%–16.2% | 19.6% | 15.4%–23.7% | 1.69 | 1.65–1.73 |
| Normal birth weight | 15.8% | 14.1%–17.6% | 14.9% | 13.6%–16.2% | 0.94 | 0.93–0.95 |
| High birth weight | 16.2% | 10.8%–21.7% | 21.2% | 16.7%–27.3% | 1.35 | 1.30–1.41 |
| Missing birth weight | 15.4% | 11.7%–19.1% | 16.8% | 14.6%–18.9% | 1.09 | 1.07–1.11 |
Note: Number of incident cases of obesity per 100 person–years between the time the children entered kindergarten and when they completed fifth grade are shown for the cohorts of United States children who entered kindergarten in 1998 and in 2010. Children with obesity in kindergarten are excluded from this table because they were not eligible for incident obesity. Race or ethnic group was reported by parents of the children or collected from school records. The category designated as “other” includes Asian American, Pacific Islander, American Indian, and multiracial background. Data: Early Childhood Longitudinal Study–Kindergarten cohorts of 1998 and 2010. CI, confidence interval.