Studies included in the review
| Author/country/year of publication | Study type | Main SES measure/s (number of categories) | Unadjusted RR/OR (95% CI)* | Gradient/trend | |
|---|---|---|---|---|---|
| Estimated | Present | ||||
| *For studies in which SES measures have more than two categories, RR/OR refers to the risk for the most versus the least disadvantaged (reference group). **Additional data obtained from authors. ***Paper includes data on study already included in papers39 and40. ¶OR adjusted for pre-natal smoking. §OR adjusted for smoking and maternal depression. †Census tracts categorised on three characterisitics: educational level; crowding; housing condition. ‡Two groups: low—father unemployed or unskilled and unmarried mothers versus rest. ††Categorised into three groups (low; middle; high) based on mother’s education and occupation. ‡‡Three categories (below average; average; above average) based on housing and education. §§Two categories (low; high) based on paternal occupation. | |||||
| Carpenter and Shaddick, UK, ’6514 | Case-control | Marital status (2) | 2.49 (1.01 to 6.27) | N/A | N/A |
| Maternal age (2) | 8.53 (1.80 to 55.5) | N/A | N/A | ||
| Steele and Langworth, Canada, ’6615 | Case-control | Maternal age (5) | 4.75 (1.34 to 18.4) | Yes | Yes |
| Valdes-Dapena et al, USA, ’6816 | Socioeconomic level (3)† | 4.59 (3.06 to 6.88) | Yes | Yes | |
| Strimer et al, USA, ’6917 | Cohort | Median income of census tracts (9) | 5.96 (3.81 to 9.36) | Yes | Yes |
| Froggatt et al, N Ireland (UK), ’7118 | Case-control | Social class (5) | 2.20(0.96 to 5.11) | Yes | Yes |
| Unemployed (2) | 2.99(1.39 to 6.53) | N/A | N/A | ||
| Persons/room (3) | 2.40(1.23 to 4.72) | Yes | Yes | ||
| Kraus et al, Canada, ’7119 | Case-control | SES (2)‡ | 2.93 (1.31 to 6.65) | N/A | N/A |
| Maternal age (2) | 5.00 (1.64 to 16.30) | N/A | N/A | ||
| Protestos et al, UK, ’7320 | Case-control | Social class (2) | 4.79 (1.37 to 6.65) | N/A | N/A |
| Marital status (2) | 1.17 (0.48 to 2.82) | N/A | N/A | ||
| Fedrick, UK, ’7419 | Cohort | Social class (5) | 3.35 (1.62 to 7.03) | Yes | Yes |
| Maternal age (2) | 4.27 (2.25 to 8.14) | N/A | N/A | ||
| Newcastle Working Party, UK, ’7722 | Case-control | Unemployed (2) | 3.45 (0.71 to 18.89) | N/A | N/A |
| Maternal age (2) | 4.47 (1.07 to 20.15) | N/A | N/A | ||
| Biering-Sorensen et al, Denmark, ’7923 | Case-control | Marital status (2) | 4.20 (2.40 to 7.32) | N/A | N/A |
| Father’s occupation (2) | 2.39 (1.47 to 4.27) | N/A | N/A | ||
| Economy of home (3) | 11.17 (3.4 to 39.10) | Yes | Yes | ||
| Persons/room (3) | 4.11 (1.50 to 11.28) | Yes | Yes | ||
| Housing quality (3) | 5.85 (2.99 to 11.75) | Yes | Yes | ||
| Lewak et al, USA, ’7924 | Cohort | Father’s occupation (2) | 2.76 (1.37 to 5.66) | N/A | N/A |
| Maternal age (2) | 2.97 (1.59 to 5.53) | N/A | N/A | ||
| Bartholomew and MacArthur, Scotland, UK, ’8825 | Case-control | Social class (not stated) | No significant difference (no figures given) | N/A | N/A |
| Maternal age (2) | 3.67 (0.88 to 17.60) | N/A | N/A | ||
| Murphy et al, Wales, UK, ’8226 | Cohort | Social class (3) | 13.42 (3.01 to 83.60) | Yes | Yes |
| Unemployed (2) | 2.78 (1.09 to 6.60) | Yes | Yes | ||
| Maternal age (3) | 6.36 (3.00 to 13.30) | Yes | Yes | ||
| Area of residence (3) | 14.34 (2.16 to >200) | Yes | Yes | ||
| Standfast et al, USA, ’8027 | Cohort | Maternal age (6) | 1.98 (1.31 to 2.97) | Yes | Yes |
| Marital status (2) | 2.3 (CI not given) | N/A | N/A | ||
| Maternal education (3) | 3.39 (CI not given) | Yes | Yes | ||
| Knowleden et al, UK, ’8528 | Case-control | Social class (5) | 3.27 (1.51 to 7.10) | Yes | Yes |
| Overcrowding (3) | 1.83 (1.13 to 2.95) | Yes | Yes | ||
| House repair (3) | 3.22 (1.77 to 5.86) | Yes | Yes | ||
| Igrens and Skjaeren, ’8629+Oyen et al ’9430+Daltvi et al ’9731 Norway | Cohort(s) (1967–1981 and 1967–1988, and 1967–1993) | Marital status (2) | (1967–1981): 1.89 (1.59 to 2.24) | N/A | N/A |
| (1990–1993): 1.57 (1.17 to 2.10) | N/A | N/A | |||
| Maternal age (4) | ‘67–’81: 2.54 (2.04 to 3.17) | Yes | Yes | ||
| ‘90–’93: 7.03 (4.17 to 11.90) | Yes | Yes | |||
| Rintahaka and Hirvonen, Finland, ’8632 | Case-control | Father’s occupation (5) | 2.68 (1.34 to 5.37) | Yes | Yes |
| Marital status (2) | 2.26 (1.34 to 3.82) | N/A | N/A | ||
| Maternal age (2) | 1.75 (1.25 to 2.45) | N/A | N/A | ||
| Victora et al, Brazil, ’8733 | Case-control | Maternal education (4) | 8.57 (2.40 to 30.80) | Yes | Yes |
| Family income (5) | 2.49 (0.85 to 7.25) | Yes | Yes | ||
| Kraus et al34+Hoffman et al35, USA, ’88 | Case-control | Income (3) | 3.9 (2.68 to 5.80) | Yes | Yes |
| Maternal education (2) | 2.7 (CI not given) | N/A | N/A | ||
| Overcrowding (2) | 2.7 (CI not given) | N/A | N/A | ||
| Marital status (2) | 3.7 (CI no given) | N/A | N/A | ||
| Maternal age (2) | 2.3 (CI not given) | N/A | N/A | ||
| Norvenius, Sweden, ’8836 | Cohort | Marital status (2) | 1.57 (1.22 to 2.03) | N/A | N/A |
| Newman, Australia, ’8837 | Cohort | Father’s occupation (2) | 1.45 (1.08 to 1.94) | N/A | N/A |
| Marital status (2) | 2.11 (1.48 to 2.99) | N/A | N/A | ||
| Maternal age (5) | 1.76 (1.01 to 3.07) | Yes | Yes | ||
| Kraus et al, USA, ’8938 | Case-control | Income (4) | 2.5 (1.6 to 4.0) | Yes | Yes |
| Maternal age (6) | 2.8 (1.0 to 6.7) | Yes | Yes | ||
| Maternal education (6) | 2.6 (1.3 to 5.3) | Yes | Yes | ||
| Housing density (4) | 1.6 (1.0 to 2.5) | Yes | Yes | ||
| McGlashan, Australia, ’8939 | Case-control | Unemployed (2) | 3.08 (CI not given) | N/A | N/A |
| Housing tenure (2) | 2.64 (CI not given) | N/A | N/A | ||
| Kyle et al, UK, ’9040 | Cohort | Social class (4) | 4.68 (1.97 to 11.11) | Yes | Yes |
| Maternal age (3) | 2.43 (1.54 to 3.83) | Yes | Yes | ||
| Li and Darling, USA, ’9141+Irwin et al ’9242 | Cohort | Maternal age (5) | 3.4 (2.6 to 4.5) | Yes | Yes |
| Marital status (2) | 2.4 (2.0 to 2.8) | N/A | N/A | ||
| Unemployed (2) | 3.05 (2.89 to 3.21) | N/A | N/A | ||
| Mitchell et al, New Zealand, ’9143+Williams et al, ’9544 | Case-control | Occupational class (3) | 3.70 (2.66 to 5.15) | Yes | Yes |
| Marital status (2) | 2.81 (1.84 to 4.29) | N/A | N/A | ||
| Maternal education (3) | 3.00 (0.92 to 9.84) | Yes | Yes | ||
| Gilbert et al, UK, ’9245 | Case-control | Social class (2) | 3.3 (1.6 to 7.0) | N/A | N/A |
| Haglund and Cnattingius, Sweden, ’906 + Nordstrom et al, ’9346 | Cohort | Cohabitation (2) | 1.82 (1.07 to 3.07) | N/A | N/A |
| Maternal education (5) | 2.88 (1.71 to 4.59) | N/A | N/A | ||
| Maternal age (4) | 4.98 (2.76 to 9.02) | Yes | Yes | ||
| Millar and Hill, Canada, ’9347 | Case-control | Maternal age (5) | 4.61 (3.43 to 6.22) | Yes | Yes |
| Marital status (2) | 3.48 (2.94 to 4.11) | N/A | N/A | ||
| Fujita and Kato, Japan, ’9448 | Cohort | Marital status (2) | 5.86 (2.37 to 14.10) | N/A | N/A |
| Maternal age (6) | 4.82 (1.09 to 20.6) | Yes | Yes | ||
| Jorch et al, Germany, ’9449 | Cohort | Maternal age (4) | 4.20 (1.70 to 10.40) | Yes | Yes |
| Maternal education (3) | 2.60 (1.50 to 4.60) | Yes | Yes | ||
| Kilkenny and Lumley, Australia, ’9450 | Cohort | Maternal age (2) | 6.24 (3.47 to 11.28) | N/A | N/A |
| Marital status (3) | 3.42 (2.61 to 4.48) | Yes | Yes | ||
| Arntzen et al, Norway, ’9551 | Cohort | Maternal education (3) | 1.35 (1.0 to 1.82) | Yes | Yes |
| Maternal age (3) | 2.18 (1.32 to 3.60) | Yes | Yes | ||
| Marital status (2) | 1.47 (0.87 to 5.90) | N/A | N/A | ||
| Klonoff-Cohen et al, USA, ’9552 | Case-control | Marital status (2) | 1.97 (1.43 to 2.71) | N/A | N/A |
| Sanghavi, USA, ’9553 | Cohort | Maternal age (2) | 1.73 (CI not given) | N/A | N/A |
| Poets et al, Germany, ’9554** | Case-control | Socioeconomic status (3)†† | 1.65 (0.85 to 3.25) | Yes | Non-significant Trend |
| Taylor and Sanderson, USA, ’9555 | Case-control | Maternal age (2) | 1.92 (1.54 to 2.38) | N/A | N/A |
| Maternal education (2) | 2.29 (1.89 to 2.79) | N/A | N/A | ||
| Alessandri et al, Australia (Aborigines only), ’9656 | Case-control | Maternal age (4) | 2.89 (1.05 to 8.00) | Yes | Yes |
| Taylor et al, USA, ’9657 | Case-control | Marital status (2) | 8.02 (3.55 to 18.28) | N/A | N/A |
| CESDI, UK, ’963 + Blair et al ’9658 | Case-control | Social class (7) | 6.95 (4.09 to 11.87) | Yes | Yes |
| Income (8) | 11.66 (3.57 to 40.6) | Yes | Yes | ||
| Parental education (6) | 2.47 (1.67 to 3.73) | Yes | Yes | ||
| Housing tenure (3) | 3.81 (2.66 to 5.50) | Yes | Yes | ||
| Overcrowding (4) | 31.3 (10.1 to 105.01) | Yes | Yes | ||
| Marital status (2) | 5.57 (2.89 to 10.83) | N/A | N/A | ||
| Receipt of income support (2) | 6.27 (4.15 to 9.47) | N/A | N/A | ||
| Kytir and Paky, Austria, ’9759 | Cohort | Maternal education (4) | 2.27 (1.84 to 2.79) | Yes | Yes |
| Maternal age (5) | 3.01 (1.94 to 4.44) | Yes | Yes | ||
| Marital status (2) | 1.41 (1.24 to 1.61) | Yes | Yes | ||
| Brooke et al, UK (Scotland), ’9758 | Case-control | Social class (7) | 2.55 (1.66 to 3.93) | Yes | Yes |
| Deprivation index (7) | 9.59 (3.32 to 27.68) | Yes | Yes | ||
| Marital status (2) | 4.22 (2.90 to 6.13) | N/A | N/A | ||
| Maternal age (2) | 2.87 (1.85 to 4.45) | N/A | N/A | ||
| Maternal education (2) | 4.28 (2.41 to 7.62) | N/A | N/A | ||
| Dalviet et al, Nordic countries (Denmark, Norway, and Sweden), ’9861 | Case-control | Marital status (2) | 2.9 (1.7 to 5.0) | N/A | N/A |
| Paternal employment (2) | 4.0 (2.7 to 5.9) | N/A | N/A | ||
| Maternal age (5) | 7.8 (2.8 to 21.5) | Yes | Yes | ||
| Maternal education (4) | 4.5 (2.8 to 7.1) | Yes | Yes | ||
| l’Hoir et al, Netherlands, ’9862 | Case-control | Maternal age (2) | 1.18 (1.01 to 1.39) | N/A | N/A |
| Socioeconomic status (2)‡‡ | 1.79 (1.01 to 3.18) | N/A | N/A | ||
| Wisborg et al, Denmark, 200063 | Cohort | Maternal age (2) | 4.39 (1.83 to 10.55) | N/A | N/A |
| Maternal education (2) | 2.23 (0.73 to 6.82) | N/A | N/A | ||
| Beal, Australia, 200064 | Cohort | Private/public patient (2) | 2.12 (1.62 to 2.77) | N/A | N/A |
| Mehanni et al, Ireland, 200065 | Cohort | Maternal age (2) | 1.78 (1.48 to 2.15) | N/A | N/A |
| Marital status (2) | 1.67 (1.40 to 2.15) | N/A | N/A | ||
| Father unemployed (2) | 2.15 (1.72 to 2.69) | N/A | N/A | ||
| Socioeconomic group (2)§§ | 1.26 (1.18 to 1.35) | N/A | N/A | ||
| Toro and Sotonyi, Hungary, 200166 | Case-control | Social disadvantage (2) | 6.7 (1.3 to 35.7) | N/A | N/A |
| Arayev et al, 17 European countries participating in the European Concerted Action on Sudden Infant Death, 200167 | Case-control | Maternal age (3) | 9.81(5.94 to 16.20) | Yes | Yes |
| Paris et al, USA, 200168 | Case-control*** (1992–1995 only) | Marital status (2) | 2.0 (1.6 to 2.5)¶ | N/A | N/A |
| Maternal age (4) | 3.4 (2.3 to 4.8)¶ | Yes | Yes | ||
| Sanderson et al, UK, 200269 | Residence in area of poverty (2) | 2.33 (1.06 to 5.11)§ | N/A | N/A | |