Table 1 Baseline characteristics of the study population, overall and by having ever had a body mass index ≥ 25 or ≥ 30 kg/m2, after multiple imputations

From: Longitudinal body mass index and cancer risk: a cohort study of 2.6 million Catalan adults

 

Overall N (%)

Never overweight (BMI < 25 kg/m2)N (%)1

Ever with overweight (BMI ≥ 25 kg/m2) N (%)1

Ever with obesity (BMI ≥ 30 kg/m2) N (%)1

 

2,645,885

812,369 (30.7)

1,833,516 (69.3)

801,612 (30.3)

Follow-up time in years, median (IQR)

9.0 (7.7, 9.0)

9.0 (7.9, 9.0)

9.0 (7.7, 9.0)

9.0 (7.5, 9.0)

Duration of BMI ≥ 25 kg/m2 in years, median (IQR)2

12.0 (0.0, 23.0)

0.0 (0.0, 0.0)

20.0 (10.0, 23.0)

23.0 (23.0, 23.0)

Duration of BMI ≥ 30 kg/m2 in years, median (IQR)

0.0 (0.0, 4.0)

0.0 (0.0, 0.0)

0.0 (0.0, 9.0)

11.0 (5.0, 20.0)

Cumulative exposure to BMI ≥ 25 kg/m2 in cumulative overweight-years, median (IQR)2,3

16.4 (0.0, 73.7)

0.0 (0.0, 0.0)

45.9 (13.7, 103.3)

113.5 (78.3, 163.3)

Cumulative exposure to BMI ≥ 30 kg/m2 in cumulative obesity-years, median (IQR)2,3

0.0 (0.0, 2.2)

0.0 (0.0, 0.0)

0.0 (0.0, 12.4)

17.4 (4.2, 51.9)

Age of onset of BMI ≥ 25 kg/m2 in years, median (IQR)2,4

20.0 (18.0, 29.0)

-

20.0 (18.0, 29.0)

18.0 (18.0, 18.0)

Age of onset of BMI ≥ 30 kg/m2 in years, median (IQR)2,4

29.0 (21.0, 35.0)

-

29.0 (21.0, 35.0)

29.0 (21.0, 35.0)

BMI at index date in kg/m2, median (IQR)2,5

27.6 (24.2, 31.1)

23.0 (20.7, 24.9)

29.4 (26.8, 32.5)

32.5 (30.5, 35.2)

Age in years, median (IQR)

56.0 (47.0, 68.0)

55.0 (46.0, 66.0)

57.0 (47.0, 70.0)

58.0 (48.0, 71.0)

Male sex, n (%)

1,241,523 (46.9)

362,147 (44.6)

879,376 (48.0)

358,172 (44.7)

Nationality

Spanish

2,495,536 (94.3)

766,176 (94.3)

1,729,360 (94.3)

756,163 (94.3)

Global North

51,320 (1.9)

17,049 (2.1)

34,271 (1.9)

14,834 (1.9)

Global South

99,029 (3.7)

29,145 (3.6)

69,884 (3.8)

30,616 (3.8)

MEDEA deprivation index, n (%)2

Quintile 1 (least deprived)

472,049 (17.8)

170,403 (21.0)

301,646 (16.5)

120,028 (15.0)

Quintile 5 (most deprived)

361,665 (13.7)

96,963 (11.9)

264,702 (14.4)

125,063 (15.6)

Smoking status, n (%)2

Never smoker

1,663,154 (62.9)

486,100 (59.8)

1,177,054 (64.2)

529,478 (66.1)

Former smoker

390,711 (14.8)

110,853 (13.6)

279,858 (15.3)

122,089 (15.2)

Current smoker

592,020 (22.4)

215,416 (26.5)

376,604 (20.5)

150,046 (18.7)

Cancer outcomes, n (%)

225,396 (8.5)

64,466 (7.9)

160,930 (8.8)

71,456 (8.9)

  1. Notes: (1) This categorization was done in the 5 datasets obtained after performing the multiple imputations. For visualization purposes and in order for the categorical variables to add up to 2,645,885 we divided the n for the categorical variables by 5. (2) The exposures of interest, the MEDEA deprivation index, smoking status, and alcohol intake were calculated using the multiple imputation approach, with 5 data sets created. For visualization purposes, we divided the n for the categorical variables by 5. (3) This indicator was calculated by adding the difference between the BMI measurements that were ≥25 ( ≥ 30, for obesity) kg/m2 and 24.9 (29.9) kg/m2 for every year lived with a BMI ≥ 25 and ≥30, respectively. (4) Age of onset of a BMI ≥ 25 (and ≥30) kg/m2 is only available for individuals who ever had a BMI ≥ 25 ( ≥ 30) kg/m2. (5) BMI assessment at the start of the time-to-event analysis (baseline BMI). A more complete description of the baseline characteristics of the study partipants can be found in Supplementary Table S6.
  2. Abbreviations: BMI Body Mass Index, IQR Interquartile range, MEDEA Mortalidad en áreas pequeñas Españolas y Desigualdades Socioeconómicas y Ambientales SIDIAP Information System for Research in Primary Care.
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