TABLE 2.
Grams of walnuts consumed, obesity prevalence, and relative fat mass by walnut consumption category, age group, and sex (n = 8874 adolescents; n = 10,323 young adults).
| Age group | Overall | Walnut classification |
P for group differences | |||
|---|---|---|---|---|---|---|
| Walnut only | Walnut with other nuts | Other nuts | No nuts | |||
| Adolescents (12-19 y) | ||||||
| Walnut consumption, g | 2.18 (0.14) | 2.2 (0.23) | 2.16 (0.23) | 0 (0) | 0 (0) | 0.917 |
| Girls | 1.87 (0.15) | 1.63 (0.20) | 2.08 (0.23) | 0 (0) | 0 (0) | 0.148 |
| Boys | 2.60 (0.26) | 2.84 (0.37) | 2.30 (0.50) | 0 (0) | 0 (0) | 0.445 |
| Obesity prevalence | 21.9% | 20.4% | 8.3% | 15.1% | 24.1% | <0.001 |
| Girls | 21.3% | 23.1% | 6.6% | 12.4% | 24.5% | <0.001 |
| Boys | 22.5% | 17.3% | 11.3% | 19.0% | 23.7% | 0.053 |
| RFM | 29.6 (0.2) | 29.3 (0.6) | 28.6 (0.8) | 29.5 (0.3) | 29.7 (0.2) | 0.574 |
| Girls | 35.3 (0.2) | 34.3 (0.7) | 32.5 (0.6) | 34 (0.3) | 35.8 (0.2) | <0.001 |
| Boys | 23.9 (0.2) | 23.7 (0.7) | 22.2 (0.9) | 23.2 (0.3) | 24.1 (0.2) | 0.046 |
| Young adults (20–39 y) | ||||||
| Walnut consumption, g | 4.23 (0.37) | 4.06 (0.43) | 4.35 (0.56) | 0 (0) | 0 (0) | 0.682 |
| Women | 3.96 (0.45) | 3.90 (0.56) | 4.01 (0.64) | 0 (0) | 0 (0) | 0.899 |
| Men | 4.57 (0.60) | 4.23 (0.68) | 4.84 (0.91) | 0 (0) | 0 (0) | 0.583 |
| Obesity prevalence | 32.6% | 25.4% | 21.1% | 28.2% | 35.4% | <0.001 |
| Women | 33.7% | 22.5% | 19.6% | 27.8% | 37.8% | <0.001 |
| Men | 31.6% | 28.6% | 23.2% | 28.7% | 33.1% | 0.095 |
| RFM | 33.3 (0.2) | 32.9 (0.6) | 32.7 (0.5) | 33.1 (0.3) | 33.4 (0.2) | 0.319 |
| Women | 39.9 (0.2) | 38.6 (0.6) | 37.8 (0.5) | 38.8 (0.3) | 40.6 (0.2) | <0.001 |
| Men | 26.7 (0.1) | 26.5 (0.5) | 25.5 (0.5) | 26.2 (0.3) | 26.9 (0.2) | 0.017 |
Abbreviations: BMI, body mass index; RFM, relative fat mass; SE, standard error.
Data shrhown as weighted means (weighted SE) for walnut consumption and RFM, and weighted proportions (percentage) for obesity prevalence. Obesity prevalence: adolescents: BMI-for-age percentile ≥95th percentile; young adults: BMI ≥30 kg/m2. RFM for adolescents aged 12–14 y was calculated using the pediatric RFM equation: RFM = 74−(22 × height/waist circumference) + 5 × sex, where sex = 1 for girls and sex = 0 for boys and height and waist circumference are expressed in meters. RFM for adolescents aged 15–19 y and young adults was calculated using the following RFM equation: RFM = 64−(20 × height/waist circumference) +12 × sex, where sex = 1 for women and sex = 0 for men and height and waist circumference are expressed in meters. P values for differences between walnut groups within age group were obtained by weighted linear regression models for walnut consumption and RFM, and Rao–Scott chi-square test for obesity prevalence. For walnut consumption, overall value and P value only used the 2 groups with walnut consumption.