Table 2.
One-Unit Increases in Early-Life Factors Predicting Point Estimates of the FI Level at Age 57 Years and the Rate of Change in FI Levels From Midlife Into Old Age
| Level* | 95% CI | p Value | Rate of Change† | 95% CI | p Value | |
|---|---|---|---|---|---|---|
| Early-life factor¶ | ||||||
| Birth factors | ||||||
| Weight (kg)‡ | −0.001 | −1.208, 1.207 | .999 | −0.087 | −0.163, −0.011 | .026 |
| Length (cm)‡ | −0.077 | −0.381, 0.227 | .619 | −0.016 | −0.034, 0.003 | .098 |
| BMI (kg/m2)‡ | 0.021 | −0.424, 0.466 | .926 | −0.029 | −0.057, −0.001 | .041 |
| Gestational age (weeks) | 0.118 | −0.221, 0.457 | .496 | −0.020 | −0.041, −0.001 | .049 |
| Maternal BMI (kg/m2)‡ | 0.263 | 0.066, 0.460 | .009 | −0.009 | −0.021, 0.003 | .134 |
| Maternal BMI (kg/m2)‡,§ | 0.218 | 0.002, 0.435 | .048 | −0.014 | −0.028, −0.002 | .026 |
| Wartime separation from both parents during World War II‖ | ||||||
| Separated | 2.190 | −0.178, 4.558 | .071 | −0.085 | −0.237, 0.067 | .275 |
| Separated × female sex | −3.429 | −6.670, −0.189 | .039 | 0.211 | 0.009, 0.414 | .041 |
| Childhood SES‖ | ||||||
| Manual worker | 2.312 | 0.889, 3.736 | .002 | −0.066 | −0.150, 0.017 | .119 |
| Lower middle class | 1.183 | −0.438, 2.805 | .153 | −0.018 | −0.114, 0.078 | .719 |
| Upper middle class | Ref. | Ref. |
Notes: CI = confidence interval; FI = frailty index; BMI = body mass index; SES = socioeconomic status.
*In FI × 100 units, which correspond percentage increases/decreases in FI levels at age 57 years (mean FI level at age 57 years was 0.186).
†In percentage points per year from midlife into old age (mean annual rate of change in FI levels from midlife into old age was 0.34%/year).
‡Model adjusted with sex, gestational age, childhood and adult SES.
§Quadratic term added, model adjusted additionally with birth weight.
‖Model adjusted with sex and adult SES.
¶Examined individually in separate models.