Table 1

Characteristics of the study subjects (all males) by working hours, Japan, 2009
7–8 hours/day 8–9 hours/day 9–10 hours/day >10 hours/day
(n = 392) (n = 177) (n = 196) (n = 168)
Characteristics No. % No. % No. % No. %
Age (years; mean, SD) 44.7 11.1 45.4 10.7 42.6 10.3 40.9 8.9
Occupation
  Clerical 14 3.6 38 21.5 27 13.8 14 8.3
  Technical 33 8.4 60 33.9 113 57.7 141 83.9
  Skilled 336 85.7 73 41.2 54 27.6 0 0.0
  Sales 5 1.3 4 2.3 2 1.0 2 1.2
  Others 3 0.8 2 1.1 0 0.0 11 6.6
  Missing 1 0.3 0 0.0 0 0.0 0 0.0
Shift work
  Non-Shift worker 253 64.5 128 72.3 148 75.5 159 94.6
  Shift worker 138 35.2 48 27.1 47 24.0 8 4.8
  Missing 1 0.3 1 0.6 1 0.5 1 0.6
Smoking status
  Never/Former 170 43.4 87 49.2 114 58.2 110 65.5
  Current 222 56.6 90 50.9 82 41.8 58 34.5
Frequency of alcohol consumption a
  None/Rarely 129 32.9 49 27.7 40 20.4 45 26.8
  Sometimes 90 23.0 55 31.1 64 32.7 74 44.1
  Often 173 44.1 73 41.2 91 46.4 49 29.2
  Missing 0 0.0 0 0.0 1 0.5 0 0.0
Cohabiting status
  Cohabiting 302 77.0 147 83.1 153 78.1 129 76.8
  Non-cohabiting 77 19.6 29 16.4 41 20.9 39 23.2
  Missing 13 3.3 1 0.6 2 1.0 0 0.0
Sleeping (hours/day; mean, SD) 6.6 1.0 6.5 0.9 6.2 0.8 5.6 0.8
Metabolic syndrome
  No 352 89.8 150 84.8 173 88.3 148 88.1
  Yes 40 10.2 27 15.3 23 11.7 20 11.9

SD standard deviation.

a Frequency of alcohol consumption categories are as follows: none/rarely, sometimes (1–3 days/month, 1–3 days/week), and often (4–6 days/week, everyday).

Kobayashi et al.

Kobayashi et al. BMC Public Health 2012 12:395   doi:10.1186/1471-2458-12-395

Open Data