Table 2

Characteristics of the final seven studies included in the review

StudyStudy populationNumber of casesComparatorLocationIPD outcomeConfounders measuredRisk factorsQuality
Flory et al20Adults ≥18 years609Regional survey data setsUSABacteraemic pneumococcal pneumoniaGender, ethnicity, age, income, education, diabetes, cancer, asthmaSmoking+/+
Jacups and Cheng21Adults (classified as ≥14 years)205Regional survey data setsAustraliaCommunity-acquired bacteraemic pneumococcal pneumoniaAge, gender, ethnicity, diabetes, alcohol, smokingSmoking, alcohol++/+
Kyaw et al16Adults ≥18 years4335National survey data setsUSAInvasive pneumococcal diseaseEthnicity, age, diabetes, chronic heart disease, chronic lung disease, cancer, HIV/AIDSAlcohol++/++
Lipsky et al22Men attending veterans medical centre63130 patients from same medical centreUSAAll pneumococcal disease including IPDAge, smokingSmoking, alcohol+/−
Nuorti et al17Adults 18–64 years228301 age-matched controlsUSA/CanadaInvasive pneumococcal diseaseSmoking
Age, gender, ethnicity, socioeconomic indicators, chronic disease, smoking status, alcohol, study area, status of children in household
Age, study area
Smoking, alcohol++/++
Pastor et al19All ages432National survey data setsUSAInvasive pneumococcal diseaseOnly crude rates reportedSmoking, alcohol−/−
Watt et al18Adults ≥18 years from Navajo Nation118353 age-matched and sex-matched controlsUSAInvasive pneumococcal diseaseSmoking
No adjustment in analysis but age-matched and sex-matched control study
Age, PPV, chronic renal failure, congestive heart failure, BMI, unemployment
Smoking, alcohol++/+
  • BMI, body mass index; IPD, invasive pneumococcal disease.