Table 1

Predictor variables for the Dementia Population Risk Tool (DemPoRT) models

VariableScaleInitial variable specificationFull modelReduced model
df
 Male model88 (65 main, 23 interaction)90 (65 main, 25 interaction)74 (51 main, 23 interaction)
 Female model88 (65 main, 23 interaction)90 (65 main, 25 interaction)74 (50 main, 24 interaction)
Socio-demographic factors
 Age*ContinuousFive knot spline: Valid range: 55–102 (male), 55–101 (female)UnchangedUnchanged
 SexCategoricalStratified: Male; femaleUnchangedUnchanged
 EthnicityCategoricalSeven categories: White; Black; Chinese; Aboriginal; Japanese/Korean/South East Asian/Filipino; other/multiple origin/unknown/Latin American; South Asian/Arab/West AsianFour categories: White; South Asian/Arab/West Asian; South East Asian/Chinese/Japanese/ Korean/Filipino; other/multiple origin/unknownExcluded (female)
 ImmigrantDichotomousYes; noUnchangedExcluded
 EducationCategoricalFour categories: Less than secondary school; secondary school graduation; some post-secondary; post-secondary graduationUnchangedExcluded (male)
 Marital statusCategoricalFour categories: Now married/common-law; separated/divorced; widowed; singleUnchangedExcluded (male)
 Neighbourhood deprivationOrdinalThree categories: Low (1st or 2nd quintile); high (4th or 5th quintile); moderate (3rd quintile)UnchangedExcluded
 MultilingualismDichotomousMultilingual; not multilingualExcluded (female)
General health
 Sense of belongingOrdinalFour categories: Very strong; somewhat strong; somewhat weak; very weakUnchangedExcluded
 StressOrdinalFive categories: Not at all stressful; not very stressful; a bit stressful; quite a bit stressful; extremely stressfulUnchangedUnchanged
 Self-rated healthOrdinalFive categories: Poor; fair; good; very good; excellentUnchangedExcluded (female)
Health behaviours
 Smoking statusCategoricalFour categories: Non-smoker; current smoker; former smoker quit <5 years ago; former smoker quit ≥5 years agoUnchangedUnchanged
 Pack years of smokingContinuousThree knot spline: Valid range: 0–112 (male), 0–78 (female)UnchangedUnchanged
 Number of drinks last weekContinuousThree knot spline: Valid range: 0–50 (male), 0–24 (female)UnchangedUnchanged
 Former drinkerDichotomousYes; noUnchangedUnchanged
 Fruit and vegetable consumptionContinuousThree knot spline: Valid range: 0–48 (male), 0–31 (female)UnchangedUnchanged
 Potato consumptionContinuousThree knot spline: Valid range: 0–2UnchangedUnchanged
 Juice consumptionContinuousThree knot spline: Valid range: 0–6 (male), 0–5 (female)UnchangedUnchanged
 Leisure physical activity
 (METs)
ContinuousThree knot spline: Valid range: 0–16 (male), 0–12 (female)UnchangedUnchanged
Functional measures
 Personal hygiene and careDichotomousDoes not need help; needs helpExcluded
 Locomotion in the homeDichotomousDoes not need help; needs helpExcluded
 Meal preparationDichotomousDoes not need help; needs helpExcluded
 Running errandsDichotomousDoes not need help; needs helpExcluded
 Ordinary houseworkDichotomousDoes not need help; needs helpExcluded
 Heavy houseworkDichotomousDoes not need help; needs helpExcluded
 FinancesDichotomousDoes not need help; needs helpExcluded
 Number of activities needing helpCategoricalSeven categories: None; 1; 2; 3; 4; 5; 6 (sum of above measures, except heavy housework)Unchanged
Health conditions
 Heart diseaseDichotomousYes; noUnchangedUnchanged
 StrokeDichotomousYes; noUnchangedUnchanged
 DiabetesDichotomousYes; noUnchangedUnchanged
 Mood disorderDichotomousYes; noUnchangedUnchanged
 High blood pressureDichotomousYes; noUnchangedUnchanged
 COPDDichotomousYes; noUnchanged
 EpilepsyDichotomousYes; noExcluded (male)
 Body mass indexContinuousThree knot spline: Valid range: 10–44 (male), 10–47 (female)UnchangedUnchanged
Design
 Survey yearOrdinalSix categories: 2001, 2003, 2005, 2007/2008, 2009/2010, 2011/2012UnchangedUnchanged
  • *Age interaction included for all variables except socio-demographic, general health and survey-year variables.

  • COPD, chronic obstructive pulmonary disease; df, degrees of freedom; MET, metabolic equivalent of task.