Table 4.

Associations between demographics and menstrual function.

	Oligomenorrhoea/amenorrhoea			History of amenorrhoea
Measurea	Prevalence (%)	OR (95% CI)	p	Prevalence (%)	OR (95% CI)	p
Age (years)
17–24	32	—	—	32	—	—
25–29	22	0.56 (0.35, 0.90)	0.018	27	0.89 (0.67, 1.19)	0.436
30–34	20	0.52 (0.30, 0.90)	0.019	26	0.90 (0.64, 1.26)	0.534
35–39	11	0.22 (0.11, 0.43)	<0.001	22	0.71 (0.47, 1.07)	0.102
40–44	13	0.32 (0.15, 0.68)	0.003	17	0.49 (0.30, 0.79)	0.004
Body mass (kg)
< 60	20	—	—	29	—	—
60–69	20	1.11 (0.75, 1.66)	0.615	26	0.91 (0.71, 1.15)	0.418
70–79	15	0.83 (0.53, 1.30)	0.404	22	0.76 (0.58, 0.98)	0.035
80–89	16	1.04 (0.61, 1.76)	0.886	20	0.68 (0.49, 0.95)	0.024
More than 90	18	1.12 (0.60, 2.05)	0.715	23	0.83 (0.55, 1.23)	0.361
Service
Army	17	—	—	26	—	—
Royal navy	17	0.88 (0.59, 1.31)	0.542	22	0.80 (0.62, 1.02)	0.076
Royal air force	20	1.16 (0.83, 1.60)	0.380	24	0.91 (0.75, 1.11)	0.366
Rank
Junior NCO and below	22	—	—	29	—	—
Senior NCO	15	0.99 (0.63, 1.58)	0.981	21	0.75 (0.56, 1.00)	0.054
Junior officer	20	1.01 (0.69, 1.48)	0.949	26	0.93 (0.73, 1.18)	0.547
Senior officer	11	0.74 (0.41, 1.30)	0.302	18	0.75 (0.54, 1.05)	0.096
Job role
Combat	12	—	—	21	—	—
Combat support	19	1.49 (0.69, 3.60)	0.341	23	0.99 (0.63, 1.59)	0.957
Combat service support	18	1.52 (0.72, 3.62)	0.303	26	1.26 (0.81, 1.99)	0.319
Length of service (years)
5 or less	25	—	—	30	—	—
6–10	20	1.01 (0.64, 1.60)	0.960	25	0.85 (0.64, 1.12)	0.245
11–15	16	1.09 (0.61, 1.95)	0.774	22	0.82 (0.57, 1.17)	0.270
16–20	12	1.05 (0.51, 2.16)	0.905	21	1.02 (0.65, 1.61)	0.930
More than 20	12	0.93 (0.41, 2.12)	0.862	18	0.94 (0.55, 1.59)	0.819
Career deployments	—	0.026b	0.124	—	0.022b	0.073
Typical sleep (hours per night)
5 or less	20	—	—	29	—	—
6–7	18	0.83 (0.54, 1.29)	0.398	25	0.79 (0.61, 1.04)	0.087
8 or more	18	0.74 (0.45, 1.22)	0.232	22	0.65 (0.48, 0.89)	0.006

CI, confidence interval; NCO, non-commissioned officer; OR, odds ratio.

^aControlling for all other factors in the table.

^bCoefficient not odds ratio.