Table 1. Subjects characteristics of the study populations.
| Characteristics LifeLines cohort | Never smokers | Former smokers | Current smokers |
| N | 3614 | 3321 | 1970 |
| Type 2 diabetes/non-diabetes | 106 (3) / 3508 (97) | 147 (4) / 3174 (96) | 56 (3) / 1914 (97) |
| Age (years) | 48 ± 12 | 53 ± 11*** | 46 ± 10 |
| Gender (male/female) n (%) | 1361 (38) / 2253 (62) | 1423 (43) / 1898 (57) | 913 (46) / 1057 (54) |
| Body mass index (kg/m2) | 26.4 ± 4.4 | 27.0 ± 4.2 *** | 26.1 ± 4.2 |
| Creatinine clearance (ml/min) | 113 ± 31 | 110 ± 31 | 119 ± 32 *** |
| Fasting blood glucose | |||
| type 2 diabetes | 7.7 ± 1.9 | 8.2 ± 2.6 | 7.8 ± 2.4 |
| non-diabetes | 5.0 ± 0.5 | 5.1 ± 0.5 *** | 5.0 ± 0.5 |
| HbA1c (%) | |||
| type 2 diabetes | 6.7 ± 1.1 | 7.0 ± 1.2 | 6.7 ± 1.2 |
| non-diabetes | 5.5 ± 0.3 | 5.6 ± 0.3 *** | 5.6 ± 0.3 |
| HbA1c (mmol/mol) | |||
| type 2 diabetes | 50.0 ± 12.3 | 52.7 ± 12.7 | 50.2 ± 12.9 |
| non-diabetes | 36.9 ± 3.3 | 37.3 ± 3.5 *** | 37.3 ± 3.4 |
| Estimated diabetes duration (years) | 6.5 (2.9–11.2) | 6.6 (3.1–12.3) | 4.3 (3.7–7.3) |
| Duration since stop smoking (years) | n.a. | 16.7 (8.0–26.4) | n.a. |
| Pack-years | n.a. | 7.7 (3.2–15.0) | 16.5 (9.6–25.0) *** |
| SAF (AU) | |||
| type 2 diabetes | 2.27 ± 0.49 | 2.48 ± 0.53 | 2.65 ± 0.61 ** |
| non-diabetes | 1.94 ± 0.40 | 2.09 ± 0.43 | 2.14 ± 0.48 *** |
| Age-adjusted SAF Z-scores | |||
| type 2 diabetes | 0.05 ± 0.16 | 0.65 ± 0.16 | 1.98 ± 0.26 *** |
| non-diabetes | -0.34 ± 0.02 | -0.15 ± 0.03 | 0.57 ± 0.04 *** |
| Characteristics QMDiab cohort | Never Smokers | Former Smokers | Current smokers |
| N | 269 | 61 | 34 |
| Type 2 diabetes/non-diabetes | 133 (49) / 136 (51) | 35 (57) / 26 (43) | 17 (50) / 17 (50) |
| Age (years) | 46 ± 13 | 51 ± 12 | 47 ± 11* |
| Gender (male/female) n (%) | 101 (38) / 168 (62) | 56 (92) / 5 (8) | 29 (85) / 5 (15) * |
| Body mass index (kg/m2) | 29.9 ± 6.3 | 28.4 ± 4.2 | 28.1 ± 4.8 |
| Ethnicity | |||
| Arab (%) | 157 (58) | 27 (44) | 18 (53) |
| South Asian (%) | 75 (28) | 25 (41) | 12 (35) |
| Filipino (%) | 27 (10) | 6 (10) | 3 (9) |
| Other or mix (%) | 10 (4) | 3 (5) | 1 (3) |
| Serum creatinine (umol/L) | 70 ± 17 | 89 ± 23 * | 77 ± 16 |
| HbA1c (%) | |||
| type 2 diabetes | 8.0 ± 1.8 | 8.3 ± 1.6 | 8.2 ± 2.4 |
| non-diabetes | 5.5 ± 0.4 | 5.7 ± 0.4 | 5.7 ± 0.4 |
| HbA1c (mmol/mol) | |||
| type 2 diabetes | 64.3 ± 19.4 | 67.2 ± 17.5 | 66.5 ± 26.2 |
| non-diabetes | 36.6 ± 4.6 | 38.5 ± 0.3 | 38.0 ± 4.7 |
| Estimated diabetes duration (years) | 10.5 ± 10.0 | 11.4 ± 10.6 | 8.7 ± 10.0 |
| Pack-years | n.a. | 10.8 ± 14.3 | 14.0 ± 13.9 |
| Cotinine (saliva, ion counts) | 51.4 x 104 ± 45.2 x 104 (n = 23) | 34.6 x 104 ± 21.2 x 104 (n = 12) | 71.4 x 104 ± 83.8 x 104 (n = 27) |
| Cotinine (plasma, ion counts) | 28.1 x 104 ± 14.4 x 104 (n = 17) | 22.3 x 104 ± 13.4 x 104 (n = 14) | 35.0 x 104 ± 19.8 x 104 (n = 30) |
| Cotinine (urine, ion counts) | 30.6 x 104 ± 67.8 x 104 (n = 37) | 43.6 x 104 ± 42.2 x 104 (n = 20) | 81.3 x 104 ± 87.1 x 104 (n = 32) * |
| Cotinine N oxide (urine, ion counts) | 3.0 x 104 ± 4.8 x 104 (n = 88) | 4.1 x 104 ± 3.8 x 104 (n = 28) | 12.9 x 104 ± 10.1 x 104 (n = 33) *** |
| Hydroxy-cotinine (urine, ion counts) | 191.8 x 104 ± 148.0 x 104 (n = 10) | 158.6 x 104 ± 68.1 x 104 (n = 5) | 277.8 x 104 ± 275.9 x 104 (n = 14) |
| SAF (AU) | |||
| type 2 diabetes | 2.43 ± 0.72 | 2.29 ± 0.58 | 2.49 ± 0.62 |
| non-diabetes | 2.10 ± 0.51 | 2.04 ± 0.58 | 2.23 ± 0.74 |
| Age-adjusted SAF Z-scores | |||
| type 2 diabetes | 0.24 ± 0.25 | 0.66 ±0.38 | 0.50 ± 0.67 |
| non-diabetes | -0.10 ± 0.18 | -0.72 ± 0.41 | -0.04 ± 0.59 |
Data are presented as means ± standard deviation, or median (interquartile range) and number (%).SAF, Skin autofluorescence; AU, Arbitrary Units.
* p<0.05
** p <0.001
*** p <0.0001