Table 1.
Baseline characteristics of 3,041 male participants according to selected male heat exposures, Pregnancy Study Online (PRESTO), 2013–2021
| Laptop use on lap (hours/day) | Sauna use (times/month) | Bath use (times/month) | Seat heater use | Type of underwear worn | Time spent sitting (hours/day) | Fever | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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| Characteristic | <1 | ≥5 | Never | ≥3 | Never | ≥3 | No | Yes | Loose boxer | Slim-fit briefs/boxer | <5 | ≥10 | None | ≥1 |
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| Number of Men (%) | 2178 (71.6) | 247 (8.1) | 2849 (93.7) | 51 (1.7) | 2104 (69.2) | 223 (7.3) | 2151 (70.7) | 890 (29.3) | 735 (24.2) | 1921 (63.3) | 711 (23.4) | 544 (17.9) | 2675 (88.0) | 366 (12.0) |
| Male age, years (mean) | 31.8 | 32.7 | 32.0 | 32.7 | 32.1 | 32.6 | 31.8 | 32.3 | 31.9 | 32.0 | 31.6 | 31.3 | 32.0 | 31.6 |
| Male education, years (mean) | 15.3 | 15.8 | 15.4 | 15.4 | 15.5 | 15.4 | 15.5 | 15.4 | 15.6 | 15.4 | 14.9 | 15.5 | 15.5 | 15.2 |
| Total MET, hours per week (mean) | 32.6 | 33.5 | 32.2 | 48.9 | 32.1 | 33.8 | 32.5 | 34.0 | 30.6 | 33.5 | 37.3 | 27.4 | 32.9 | 33.8 |
| Cycles of attempt time at study entry (mean) | 1.8 | 1.9 | 1.8 | 1.8 | 1.8 | 1.9 | 1.9 | 1.7 | 1.8 | 1.8 | 1.9 | 1.9 | 1.8 | 1.8 |
| Household income <$50,000 USD (%) | 16.6 | 10.0 | 15.5 | 16.3 | 14.3 | 25.1 | 17.2 | 10.2 | 14.5 | 14.6 | 20.0 | 12.7 | 14.7 | 19.6 |
| Household income ≥$150,000 USD (%) | 18.2 | 27.4 | 20.0 | 24.6 | 20.2 | 15.9 | 17.5 | 26.9 | 19.0 | 21.4 | 13.8 | 23.7 | 19.8 | 24.7 |
| White, non-Hispanic (%) | 84.9 | 76.3 | 84.4 | 87.9 | 85.2 | 77.4 | 84.8 | 83.6 | 84.8 | 84.3 | 85.3 | 83.0 | 84.6 | 83.3 |
| Male alcohol intake: None (%) | 21.5 | 18.1 | 21.6 | 18.2 | 22.1 | 24.1 | 23.1 | 15.5 | 22.1 | 21.7 | 20.5 | 22.8 | 20.3 | 27.1 |
| Male alcohol intake: ≥14 drinks/week (%) | 12.9 | 8.1 | 11.8 | 28.8 | 11.7 | 13.0 | 12.8 | 11.2 | 13.8 | 11.2 | 16.4 | 13.1 | 12.4 | 11.2 |
| Male BMI <25 m/kg2 (%) | 31.2 | 28.7 | 31.5 | 27.2 | 31.1 | 35.2 | 31.9 | 31.4 | 35.7 | 29.5 | 28.5 | 24.7 | 32.6 | 25.8 |
| Male BMI ≥30 m/kg2 (%) | 32.0 | 33.1 | 31.2 | 30.8 | 32.2 | 27.2 | 32.0 | 28.4 | 26.8 | 32.8 | 30.4 | 39.1 | 29.9 | 38.4 |
| Current smoker (%) | 13.2 | 8.5 | 12.5 | 9.6 | 12.2 | 11.6 | 12.7 | 10.9 | 11.1 | 12.6 | 13.8 | 11.7 | 11.9 | 14.8 |
| Former smoker (%) | 16.5 | 16 | 15.6 | 33.1 | 15.9 | 24.2 | 15.1 | 17.2 | 12.9 | 16.2 | 19.3 | 15.5 | 15.2 | 20.5 |
| Male sleep duration: <6 hours/day (%) | 8.7 | 6.1 | 8.9 | 13.8 | 8.2 | 12.7 | 8.6 | 8.9 | 10.5 | 7.6 | 11.4 | 9.3 | 8.4 | 11.8 |
| Male sleep duration: ≥9 hours/day (%) | 3.7 | 5.5 | 3.5 | 1.5 | 3.6 | 1.8 | 3.7 | 3.4 | 3.2 | 3.9 | 2.6 | 6.5 | 3.8 | 2.7 |
| Job hours1 <30 hours/week (%) | 6.5 | 4.6 | 6.4 | 3.6 | 6.2 | 10.4 | 6.9 | 4.9 | 5.5 | 6.3 | 5.7 | 4.9 | 6.3 | 5.8 |
| Job hours1 ≥50 hours/week (%) | 22.7 | 25.8 | 23.0 | 42.7 | 23.1 | 24.9 | 23.9 | 22.7 | 21.7 | 24.4 | 27.1 | 22.5 | 23.1 | 27.7 |
| Unemployed (%) | 5.8 | 7.5 | 5.3 | 2.3 | 5.0 | 5.3 | 5.2 | 6.0 | 4.6 | 5.6 | 5.0 | 5.0 | 5.7 | 3.7 |
| Laptop use on lap <1 hour/day (%) | -- | -- | 72.8 | 54.5 | 73.2 | 65.7 | 72.8 | 70.1 | 71.7 | 72.1 | 78.2 | 65.0 | 72.9 | 66.7 |
| Laptop use on lap ≥3 hours/day (%) | -- | -- | 5.1 | 7.8 | 5.5 | 2.9 | 4.9 | 5.9 | 3.7 | 5.9 | 4.9 | 6.2 | 4.8 | 7.7 |
| Sauna use, never (%) | 94.2 | 87.9 | -- | -- | 97.4 | 85.1 | 94.2 | 91.1 | 94.7 | 93.1 | 93.6 | 93.9 | 92.9 | 95.7 |
| Sauna use, ≥3/month (%) | 1.2 | 4.5 | -- | -- | 0.9 | 6.7 | 1.4 | 2.5 | 1.2 | 1.8 | 2.0 | 1.7 | 1.7 | 1.9 |
| Hot tub/bath use, never (%) | 70 | 62.3 | 72.1 | 41.1 | -- | -- | 71.7 | 62.3 | 73.7 | 68.3 | 69.3 | 71.9 | 69.2 | 67.2 |
| Hot tub/bath use, ≥3/month (%) | 6.9 | 13.5 | 6.9 | 29.6 | -- | -- | 7.3 | 8.1 | 4.9 | 8.6 | 8.1 | 6.6 | 7.3 | 8.6 |
| Seat heater use in winter (%) | 28 | 37.1 | 28.0 | 43.1 | 25.9 | 30.6 | -- | -- | 25.2 | 30.5 | 29.3 | 32.6 | 29.1 | 25.1 |
| Slim-fit boxer (%) | 61.7 | 64.1 | 61.6 | 68.6 | 61.1 | 70.6 | 60.0 | 65.5 | -- | -- | 61.4 | 60.9 | 61.3 | 65.2 |
| Sit <5 hours/day (%) | 24.7 | 7.5 | 22.9 | 31.8 | 22.9 | 23.5 | 22.6 | 23.5 | 22.5 | 22.7 | -- | -- | 22.9 | 21.9 |
| Sit ≥10 hours/day (%) | 16.2 | 26.6 | 18.0 | 16.2 | 18.5 | 17 | 16.9 | 20.3 | 18.7 | 17.7 | -- | -- | 17.7 | 18.9 |
| Fever within 3 months, % | 11.1 | 13.7 | 12.3 | 11.6 | 11.7 | 13.9 | 12.6 | 10.6 | 11.8 | 12.6 | 11.4 | 13.0 | -- | -- |
| Previously fathered a child, % | 42.9 | 34.0 | 42.0 | 34.4 | 41.1 | 44.8 | 41.9 | 40.2 | 41.5 | 41.6 | 46.9 | 38.1 | 40.0 | 51.8 |
a
Excludes unemployed