Unadjusted and adjusted odds ratios for severe sepsis associated with sociodemographic and medical factors; all severe sepsis cases compared with controls.

*Percentage of individuals with complete data.**Adjusted for all factors in the table. Age treated as a continuous linear term in the analysis, but presented as a categorical term.***As per the National Statistics Socio-Economic Classification (http://www.ons.gov.uk/ons/guide-method/classifications/current-standard-classifications/soc2010/soc2010-volume-3-ns-sec—rebased-on-soc2010—user-manual/index.html).****Major pre-existing medical problems (percent cases versus controls) include asthma (10.0% versus 17.0%), endocrine disorders (5.8% versus 9.4%), haematological disorders (9.2% versus 7.0%), mental health/psychiatric disorders (13.3% versus 12.9%), renal disorders (7.5% versus 1.8%), and unknown medical problem (18.3% versus 15.8%).*****Chorionic villus sampling, amniocentesis, etc.