Skip to main content

Advertisement

Table 2 Distribution of Demographic and Socioeconomic Variables Among Included Controls by Mailing Wave in a Case-Control Study of Campylobacter Enteritis, England 2005-6

From: Effect of reminders on mitigating participation bias in a case-control study

  Group 1A 1B 1C  
   First mailing First reminder Second reminder Total§
Sex Female 56.0% 49.5% 51.9% 53.3%
χ 2 p = 0.004 Male 44.0% 50.5% 48.1% 45.2%
  Total 2507 703 717 3927
Age group 18-24 5.4% 6.0% 10.3% 6.3%
χ 2 p < 0.001 25-34 12.6% 13.1% 14.8% 12.9%
  35-44 19.0% 20.5% 24.7% 20.0%
  45-54 20.0% 21.2% 20.8% 20.1%
  55-64 20.0% 19.2% 15.1% 18.7%
  65+ 23.1% 20.1% 14.4% 20.7%
  Total 2507 703 717 3927
Age at leaving full-time education < 16 yrs 28.3% 30.9% 26.1% 28.3%
χ 2 p = 0.007 16 yrs 29.4% 29.3% 34.6% 30.4%
  17 yrs 9.0% 9.5% 8.8% 9.0%
  18 yrs 11.5% 9.1% 10.3% 10.9%
  19 yrs 20.5% 19.2% 17.1% 19.6%
  Still in education 1.3% 1.9% 3.1% 1.8%
  Total 2463 692 706 3861
IMD quintile 1 (most deprived) 15.2% 18.4% 19.0% 16.5%
χ 2 p = 0.056 2 16.0% 14.8% 18.6% 16.2%
  3 20.3% 18.8% 19.0% 19.8%
  4 22.5% 21.2% 19.0% 21.6%
  5 26.0% 26.8% 24.4% 25.9%
  Total 2483 697 710 3890
  1. § 56 individuals could not be assigned to any group due to missing date information
  2. Age at leaving full-time education was missing for 66 individuals
  3. IMD quintile was missing for 71 individuals