Characteristics of 7319 male singletons in the cohort. Percentage with birth weight below 2500 g, percentage in the lowest quartile of cognitive tests, and crude risk of all cause mortality between age 15–49 years (95% confidence intervals) according to characteristics
| N (%) | Birth weight below 2500 g (%) | Lowest IQ test quartile (%) | Lowest creativity test quartile (%) | Crude hazard ratio | |
|---|---|---|---|---|---|
| *p<0.05, test of β coefficients from logistic regression. Unmarked category reference. Similar differences were found for mean vaules tested in linear regression. | |||||
| Socioeconomic position in early life | |||||
| Father’s social class at time of birth | |||||
| High/middle class | 3331 (45.5) | 3.0 | 17.9 | 22.9 | 1.00 (ref) |
| Working class | 3543 (48.4) | 4.1* | 33.1* | 34.5* | 1.41 (1.17 to 1.69) |
| Unknown | 445 (6.0) | 5.8* | 36.9* | 32.9* | 2.00 (1.46 to 2.74) |
| Mother’s marital status at time of birth | |||||
| Married | 6821 (93.3) | 3.5 | 25.4 | 28.6 | 1.00 (ref) |
| Unmarried | 481 (6.7) | 6.5* | 39.3* | 33.8* | 1.56 (1.17 to 2.07) |
| Unknown | 7 (0.0) | – | |||
| Birth weight | |||||
| −2499 g | 269 (3.7) | 33.8* | 40.1* | 1.69 (1.14 to 2.51) | |
| 2500–3499 g | 3644 (49.8) | 26.6 | 28.4 | 1.23 (1.03 to 1.47) | |
| 3500 g+ | 3402 (46.5) | 25.4 | 28.9 | 1.00 (ref) | |
| Unknown | 4 (0.0) | – | |||
| Cognitive function at age 12 years | |||||
| Härnquist IQ test | |||||
| Lowest quartile | 1924 (26.3) | 4.7* | 54.7* | 1.71 (1.34 to 2.19) | |
| Second quartile | 1840 (25.1) | 4.6* | 32.4* | 1.30 (1.00 to 1.69) | |
| Third quartile | 1784 (24.4) | 3.3* | 17.8* | 1.12 (0.83 to 1.47) | |
| Highest quartile | 1771 (24.2) | 1.9 | 9.0 | 1.00 (ref) | |
| Creativity test | |||||
| Lowest quartile | 2126 (29.1) | 5.1* | 49.5* | 1.48 (1.16 to 1.82) | |
| Second quartile | 1755 (24.0) | 3.8* | 27.8* | 1.27 (0.98 to 1.65) | |
| Third quartile | 1618 (22.1) | 3.2* | 17.6* | 1.23 (0.95 to 1.61) | |
| Highest quartile | 1820 (24.9) | 2.3 | 5.5 | 1.00 (ref) | |