Table 3.
Comparisons between quantitative MWS and corresponding NSHD variables
| Difference | Scaled 95% limits | Intraclass | Pearson | |||||
|---|---|---|---|---|---|---|---|---|
| MWS | NSHD | (MWS - NSHD) | of agreement | correlation | correlation | |||
| Variable (units) | N | mean (SD) | mean (SD) | mean (SD) | P* | lower to upper† | ICC (SE) ‡ | r (SE) |
| Self-reported at recruitment in the MWS | ||||||||
| Height (cm) | 449 | 162.8 (6.3) | 162.0 (5.7) | 0.9 (2.7) | <0.001 | -0.8 to 1.1 | 0.89 (0.01) | 0.91 (0.01) |
| Weight (kg) | 443 | 68.8 (13.1) | 71.0 (14.1) | -2.2 (4.2) | <0.001 | -0.7 to 0.4 | 0.94 (0.006) | 0.95 (0.004) |
| Body mass index (kg/m2) | 437 | 25.9 (4.7) | 27.0 (5.2) | -1.1 (2.0) | <0.001 | -1.0 to 0.5 | 0.90 (0.01) | 0.92 (0.01) |
| Age at menarche (yr) | 394 | 13.0 (1.4) | 12.9 (1.0) | 0.1 (1.2) | 0.093 | -2.1 to 2.3 | 0.54 (0.04) | 0.57 (0.03) |
| Age at menopause (yr) | 134 | 48.0 (4.5) | 48.2 (4.2) | -0.3 (1.8) | 0.091 | -0.9 to 0.8 | 0.92 (0.01) | 0.92 (0.01) |
| Self-reported at resurvey in the MWS | ||||||||
| Birth weight (kg) | 234 | 3.2 (0.7) | 3.3 (0.5) | -0.1 (0.4) | <0.001 | -1.8 to 1.4 | 0.75 (0.03) | 0.78 (0.03) |
| Mother's height (cm) | 294 | 160.4 (7.1) | 161.4 (6.5) | -0.9 (5.2) | 0.002 | -1.7 to 1.4 | 0.70 (0.03) | 0.71 (0.03) |
| Father's height (cm) | 240 | 174.1 (7.6) | 173.7 (7.9) | 0.3 (6.3) | 0.451 | -1.5 to 1.6 | 0.67 (0.04) | 0.67 (0.04) |
| Waist circumference (cm) | 206 | 76.0 (9.3) | 82.0 (10.6) | -6.0 (7.2) | <0.001 | -1.9 to 0.8 | 0.59 (0.05) | 0.74 (0.03) |
| Hip circumference (cm) | 204 | 100.0 (8.3) | 103.1 (8.5) | -3.2 (5.3) | <0.001 | -1.6 to 0.9 | 0.74 (0.03) | 0.80 (0.03) |
| Waist-to-hip ratio | 197 | 0.76 (0.06) | 0.79 (0.06) | -0.03 (0.06) | <0.001 | -2.4 to 1.3 | 0.41 (0.06) | 0.52 (0.05) |
| Waist-to-height ratio | 204 | 0.47 (0.06) | 0.51 (0.07) | -0.04 (0.04) | <0.001 | -1.9 to 0.7 | 0.60 (0.05) | 0.75 (0.03) |
MWS: Million Women Study. NSHD: National Survey of Health and Development. N: numbers of women with non-missing values for both MWS and NSHD variables. r: Pearson correlation. SE: standard error.
* P-value for t-test of mean difference = 0.
† Lower to upper Bland-Altman limits of agreement divided by the SD of the NSHD data.
‡ ICC(1,1) in the notation of Shrout and Fleiss [26].