TABLE 1.
Baseline characteristics of mobile phone users according to weekly usage time of mobile phones making or receiving calls (UK, 2006–2010).
| Baseline characteristics a | Weekly usage time of mobile phone making or receiving calls | p-value | |||||
|---|---|---|---|---|---|---|---|
| <5mins | 5–29 min | 30–59 min | 1–3 h | 4–6 h | >6 h | ||
| N | 71,891 | 135,929 | 60,562 | 50,273 | 14,797 | 15,150 | |
| Age, years | 58.4 ± 7.6 | 56.5 ± 7.9 | 54.8 ± 7.8 | 53.0 ± 7.7 | 51.6 ± 7.4 | 50.4 ± 7.0 | <0.001 |
| Male, n (%) | 31,896 (44.4) | 57,623 (42.4) | 28,178 (46.5) | 25,839 (51.4) | 8,059 (54.5) | 8,678 (57.3) | <0.001 |
| White, n (%) | 69,367 (96.5) | 130,459 (96.0) | 57,356 (94.7) | 46,611 (92.7) | 13,554 (91.6) | 13,662 (90.2) | <0.001 |
| Body mass index, kg/m2 | 27.0 ± 4.5 | 27.2 ± 4.6 | 27.5 ± 4.7 | 27.7 ± 4.7 | 28.1 ± 4.8 | 28.4 ± 4.9 | <0.001 |
| Systolic blood pressure, mmHg | 139.1 ± 18.5 | 137.3 ± 18.2 | 135.7 ± 17.9 | 134.6 ± 17.4 | 134.0 ± 17.0 | 133.3 ± 16.8 | <0.001 |
| Diastolic blood pressure, mmHg | 82.1 ± 9.9 | 82.0 ± 9.9 | 81.9 ± 10.0 | 82.1 ± 10.1 | 82.3 ± 10.2 | 82.5 ± 10.2 | <0.001 |
| Townsend deprivation index | −1.7 ± 2.9 | −1.5 ± 3.0 | −1.2 ± 3.1 | −1.1 ± 3.2 | −1.0 ± 3.2 | −1.0 ± 3.3 | <0.001 |
| College or University degree, n (%) | 23,011 (32.3) | 45,766 (33.9) | 20,593 (34.2) | 16,887 (33.8) | 4,707 (32.1) | 4,528 (30.1) | <0.001 |
| Current smoker, n (%) | <0.001 | ||||||
| Never | 40,846 (57.0) | 74,406 (54.9) | 31,569 (52.3) | 26,021 (51.9) | 7,731 (52.4) | 7,726 (51.2) | |
| Former | 25,016 (34.9) | 48,569 (35.8) | 21,994 (36.4) | 17,468 (34.8) | 4,828 (32.7) | 4,751 (31.5) | |
| Current | 5,796 (8.1) | 12,562 (9.3) | 6,817 (11.3) | 6,640 (13.2) | 2,188 (14.8) | 2,622 (17.4) | |
| Alcohol drinking, n (%) | <0.001 | ||||||
| Never | 5,457 (7.6) | 8,794 (6.5) | 3,917 (6.5) | 3,361 (6.7) | 1,042 (7.0) | 1,194 (7.9) | |
| <1 time per week | 16,291 (22.7) | 29,494 (21.7) | 12,535 (20.7) | 10,471 (20.8) | 3,138 (21.2) | 3,244 (21.4) | |
| 1–4 time per week | 35,139 (48.9) | 69,528 (51.2) | 31,253 (51.6) | 25,801 (51.4) | 7,687 (52.0) | 7,576 (50.1) | |
| Daily or almost daily | 14,959 (20.8) | 28,043 (20.7) | 12,828 (21.2) | 10,612 (21.1) | 2,923 (19.8) | 3,122 (20.6) | |
| Income, n (%) | <0.001 | ||||||
| Not to answer/Do not know | 10,699 (14.9) | 17,338 (12.8) | 7,096 (11.7) | 5,254 (10.5) | 1,513 (10.2) | 1,477 (9.8) | |
| Less than 18,000 | 15,608 (21.8) | 24,275 (17.9) | 9,591 (15.9) | 7,110 (14.2) | 1934 (13.1) | 1892 (12.5) | |
| 18,000 to 30,999 | 17,455 (24.3) | 30,594 (22.6) | 12,212 (20.2) | 9,121 (18.2) | 2,409 (16.3) | 2,269 (15.0) | |
| 31,000 to 51,999 | 15,581 (22.1) | 32,255 (23.8) | 14,763 (24.4) | 12,442 (24.8) | 3,581 (24.2) | 3,637 (24.0) | |
| 52,000 to 100,000 | 10,112 (14.1) | 25,002 (18.4) | 13,001 (21.5) | 12,197 (24.3) | 3,889 (26.3) | 4,171 (27.6) | |
| Greater than 100,000 | 1971 (2.7) | 6,193 (4.6) | 3,767 (6.2) | 4,053 (8.1) | 1,448 (9.8) | 1,682 (11.1) | |
| LDL cholesterol, mmol/L | 3.6 ± 0.9 | 3.6 ± 0.9 | 3.6 ± 0.9 | 3.6 ± 0.8 | 3.6 ± 0.8 | 3.6 ± 0.8 | 0.003 |
| HDL cholesterol, mmol/L | 1.5 ± 0.4 | 1.5 ± 0.4 | 1.4 ± 0.4 | 1.4 ± 0.4 | 1.4 ± 0.4 | 1.4 ± 0.4 | <0.001 |
| Triglycerides, mmol/L | 1.7 ± 1.0 | 1.7 ± 1.0 | 1.7 ± 1.0 | 1.8 ± 1.1 | 1.8 ± 1.1 | 1.9 ± 1.2 | <0.001 |
| HbA1c, % | 5.4 ± 0.6 | 5.4 ± 0.5 | 5.4 ± 0.6 | 5.4 ± 0.6 | 5.4 ± 0.6 | 5.4 ± 0.6 | <0.001 |
| C-reactive protein, mg/L | 2.5 ± 4.1 | 2.5 ± 4.1 | 2.5 ± 4.2 | 2.5 ± 4.0 | 2.5 ± 4.0 | 2.6 ± 4.0 | 0.006 |
| eGFR, mL/min/1.73m2 | 90.3 ± 11.7 | 91.6 ± 11.9 | 92.8 ± 11.9 | 94.1 ± 12.0 | 94.8 ± 12.1 | 95.4 ± 12.2 | <0.001 |
| Antihypertensive medications use, n (%) | 15,392 (21.5) | 26,086 (19.3) | 10,364 (17.2) | 7,770 (15.6) | 2056 (14.0) | 2004 (13.4) | <0.001 |
| Cholesterol lowering medications use, n (%) | 13,046 (18.3) | 21,687 (16.0) | 8,855 (14.7) | 6,502 (13.0) | 1742 (11.9) | 1717 (11.4) | <0.001 |
| Glucose-lowering medications use, n (%) | 2,199 (3.1) | 3,791 (2.8) | 1820 (3.0) | 1,421 (2.8) | 409 (2.8) | 439 (2.9) | 0.005 |
| Length of mobile phone use, n (%) | <0.001 | ||||||
| One year or less | 5,639 (7.8) | 3,930 (2.9) | 742 (1.2) | 360 (0.7) | 64 (0.4) | 49 (0.3) | |
| Two to four years | 22,152 (30.8) | 31,367 (23.1) | 9,805 (16.2) | 5,512 (11.0) | 1,229 (8.3) | 804 (5.3) | |
| Five to eight years | 26,707 (37.1) | 53,784 (39.6) | 22,447 (37.1) | 16,342 (32.5) | 4,112 (27.8) | 3,129 (20.7) | |
| More than eight years | 17,393 (24.2) | 46,848 (34.5) | 27,568 (45.5) | 28,059 (55.8) | 9,392 (63.5) | 11,168 (73.7) | |
| Hands-free device/speakerphone use, n (%) | <0.001 | ||||||
| Never or almost never | 68,370 (95.1) | 120,505 (88.7) | 47,696 (78.8) | 33,662 (67.0) | 8,127 (54.9) | 6,973 (46.0) | |
| Less than half the time | 1903 (2.6) | 9,095 (6.7) | 7,274 (12.0) | 8,843 (17.6) | 3,133 (21.2) | 3,285 (21.7) | |
| About half the time | 673 (0.9) | 2,960 (2.2) | 2,694 (4.4) | 3,506 (7.0) | 1,515 (10.2) | 1,673 (11) | |
| More than half the time | 278 (0.4) | 1,378 (1.0) | 1,325 (2.2) | 2031 (4.0) | 951 (6.4) | 1,338 (8.8) | |
| Always or almost always | 667 (0.9) | 1991 (1.5) | 1,573 (2.6) | 2,231 (4.4) | 1,071 (7.2) | 1881 (12.4) | |
a
The results are presented as Mean ± SD or n (%).
Abbreviations: eGFR, estimated glomerular filtration rate; HbA1c, glycosylated hemoglobin, HDL cholesterol, high density lipoprotein cholesterol; LDL cholesterol, low density lipoprotein cholesterol.