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Table 1 Questionnaire response rates by early life factors

From: Early life factors, childhood cognition and postal questionnaire response rate in middle age: the Aberdeen Children of the 1950sstudy

  Male Female
  Number Response rate (%) Odds ratio (95% CI) Number Response rate (%) Odds ratio (95% CI)
Sex         
Male 5,742 59.8 1.00      
Female 5,540 67.7 1.41 (1.31 to 1.52)     
Birth weight (lbs)         
<6.5 1,118 58.7 1.00   1,451 65.0 1.00*  
6.5–7.5 1,874 588 1.00 (0.86 to 1.17) 2,061 68.3 1.16 (1.01 to 1.34)
7.5–8.5 1,809 60.7 1.09 (0.93 to 1.27) 1,480 69.6 1.23 (1.06 to 1.44)
≥8.5 929 61.0 1.10 (0.92 to 1.32) 539 68.3 1.16 (0.94 to 1.43)
Missing† 12 83.3    9 22.2   
Mother's marital status at birth        
Single/widowed/divorced 175 52.0 1.00   190 50.5 1.00  
Married 5,564 60.0 1.39 (1.02 to 1.87) 5,349 68.3 2.11 (1.58 to 2.83)
Missing† 3 66.7    1 0.0   
Father's social class at birth         
Unemployed/disabled/deceased 297 52.9 1.00*   336 56.9 1.00*  
IV/V 1,765 55.9 1.13 (0.88 to 1.45) 1,633 63.4 1.32 (1.04 to 1.67)
III Manual 2,486 59.7 1.32 (1.04 to 1.68) 2,442 68.4 1.64 (1.30 to 2.07)
III Non-manual 633 65.9 1.72 (1.30 to 2.29) 613 73.9 2.15 (1.62 to 2.86)
I/II 561 69.2 2.00 (1.49 to 2.68) 515 77.9 2.67 (1.96 to 3.63)
Missing† 0     1 0.0   
Father's social class in 1962         
Unemployed/disabled/deceased 341 46.6 1.00*   357 53.5 1.00*  
IV/V 1,424 55.4 1.42 (1.12 to 1.80) 1,419 64.3 1.57 (1.24 to 1.98)
III Manual 2,419 60.0 1.72 (1.36 to 2.16) 2,291 68.0 1.84 (1.47 to 2.31)
III Non-manual 701 67.3 2.36 (1.80 to 3.09) 630 73.2 2.37 (1.79 to 3.13)
I/II 776 67.8 2.41 (1.85 to 3.14) 781 76.6 2.84 (2.16 to 3.73)
Missing 81 43.2 0.87 (0.54 to 1.42) 62 50.0 0.87 (0.51 to 1.48)
Number of siblings in 1962         
5 or more 1,041 50.4 1.00*   946 59.2 1.00*  
4 938 57.7 1.34 (1.12 to 1.60) 942 65.2 1.29 (1.07 to 1.56)
3 1,424 61.5 1.57 (1.34 to 1.85) 1,420 70.9 1.67 (1.41 to 1.99)
2 1,749 64.2 1.76 (1.50 to 2.06) 1,677 71.3 1.71 (1.45 to 2.03)
1 545 64.6 1.79 (1.45 to 2.22) 510 68.8 1.52 (1.21 to 1.91)
Missing 45 35.6 0.54 (0.29 to 1.00) 45 53.3 0.79 (0.44 to 1.42)
Height for age at 1st medical exam 1962
≤-1 734 54.4 1.00*   872 62.3 1.00*  
-1 to 0 1,882 57.1 1.12 (0.94 to 1.33) 1,969 66.0 1.17 (1.00 to 1.39)
0 to 1 2,139 62.3 1.39 (1.17 to 1.65) 1,775 69.9 1.40 (1.18 to 1.67)
≥1 737 66.9 1.70 (1.37 to 2.10) 723 73.7 1.70 (1.37 to 2.11)
Missing 250 52.8 0.94 (0.70 to 1.25) 201 67.7 1.27 (0.92 to 1.75)
Weight for age at 1st medical exam (SD)
≤-1 870 56.7 1.00*   795 63.9 1.00*  
-1 to 0 2,045 59.5 1.12 (0.96 to 1.32) 2,109 65.5 1.07 (0.91 to 1.27)
0 to 1 1,810 59.2 1.11 (0.94 to 1.31) 1,667 70.0 1.32 (1.10 to 1.58)
≥1 767 67.8 1.61 (1.31 to 1.97) 769 72.7 1.50 (1.21 to 1.87)
Missing 250 52.8 0.86 (0.65 to 1.13) 200 67.5 1.17 (0.84 to 1.63)
Rutter B behavioral score         
9+ 595 47.4 1.00*   320 57.2 1.00*  
3–8 1,736 56.2 1.42 (1.18 to 1.72) 1,448 61.5 1.19 (0.93 to 1.53)
1–2 1,517 63.8 1.96 (1.61 to 2.38) 1,637 69.6 1.72 (1.34 to 2.20)
0 1,720 65.7 2.13 (1.75 to 2.58) 1,990 73.3 2.06 (1.61 to 2.63)
Missing 174 44.3 0.88 (0.63 to 1.24) 145 54.5 0.90 (0.60 to 1.33)
  1. * p < 0.05 for the score test for trend (missings were not included).
  2. † We did not calculate odds ratio and 95% confidence interval due to small sample size.
  3. ‡ p < 0.05 for the interaction with sex tested by using likelihood ratio test in logistic regression.