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Table 1 Characteristics of the study population

From: The frailty index is a predictor of cause-specific mortality independent of familial effects from midlife onwards: a large cohort study

  Men (N = 19,924) Women (N = 23,029)
Single respondersa DZ twinsb MZ twins Single respondersa DZ twinsb MZ twins
Number of participantsc 15,473 5266 3636 17,321 6546 4870
Age at baseline, mean (SD) 58.7 (10.6) 57.4 (9.6) 56.9 (9.2) 59.6 (11.2) 58.5 (10.3) 57.8 (10.2)
BMI (kg/m2), mean (SD) 25.5 (3.1) 25.6 (3.1) 25.5 (3) 24.6 (3.7) 24.5 (3.7) 24.4 (3.8)
Education (year), mean (SD) 10.4 (3.2) 10.6 (3.2) 10.8 (3.2) 10.4 (3.2) 10.5 (3.2) 10.8 (3.2)
Tobacco products used, % 64.3 63.1 59.5 53.9 54.3 52.5
FI, median (IQR) 0.097 (0.102) 0.094 (0.097) 0.091 (0.097) 0.125 (0.125) 0.119 (0.125) 0.119 (0.119)
History of diseases at baseline, %
 CVD 35.5 34.0 31.5 37.4 35.6 34.8
 Respiratory disease 9.6 8.2 9.6 11.9 10.8 11.7
 Cancer 4.7 4.2 4.7 9.1 8.5 9.3
Time to follow-up, median (IQR)
 All-cause mortality 16.7 (2.8) 16.9 (2.4) 16.9 (2.3) 16.9 (2.6) 17.0 (2.5) 17.1 (2.4)
 Cause-specific mortality 14.0 (2.5) 14.1 (2.3) 14.1 (2.3) 14.2 (2.5) 14.3 (2.2) 14.3 (2.3)
Death during the follow-up, %
 All causes 31.3 26.0 23.4 28.3 25.0 22.1
 CVD 8.9 7.0 5.7 7.4 6.1 4.8
 Respiratory-related causes 2.7 2.1 1.9 2.4 2.2 1.7
 Cancer 9.0 7.7 7.5 7.0 6.7 5.9
  1. aSingle responders included twins whose partner did not respond in SALT, twins from opposite-sex twin pairs, and one randomly selected member of each same-sex twin pair
  2. bDZ twins refer to the same-sex DZ twins
  3. cNumber of participants refers to the number of single responders or the number of individuals in DZ/MZ twin pairs
  4. dParticipants who used tobacco products include current smokers, ex-smokers, and snuff users at baseline