Table 1. Characteristics of the study population, by country.
| Total (N=518) | Uganda (N=187) | Zimbabwe (N=331) | p value | |
|---|---|---|---|---|
| Age (years) | 29 (25, 32) | 28 (24, 31) | 29 (25, 32) | 0.452 |
| Body mass index (kg/m2) | 24.8 (22.2, 28.6) | 24.5 (22.2, 29.0) | 24.9 (22.2, 28.6) | 0.984 |
| Parity (children) | 2 (2, 3) | 3 (2, 4) | 2 (2, 3) | 0.0001 |
| Earns own income (N, %) | 279 (54 %) | 138 (74 %) | 141 (43 %) | <0.0001 |
| Education level (N, %) | <0.0001 | |||
| No schooling | 15 (3 %) | 14 (7 %) | 1 (<1 %) | |
| Primary school, not complete | 87 (17 %) | 81 (43 %) | 6 (2 %) | |
| Primary school, complete | 47 (9 %) | 19 (10 %) | 28 (8 %) | |
| Secondary school, not complete | 150 (29 %) | 61 (33 %) | 89 (27 %) | |
| Secondary school, complete | 207 (40 %) | 7 (4 %) | 200 (60 %) | |
| Attended college or university | 12 (2 %) | 5 (3 %) | 7 (2 %) | |
| Married (N, %) | 410 (79 %) | 100 (53 %) | 310 (94 %) | <0.0001 |
| Alcohol consumption, past 3 months (N, %) | <0.0001 | |||
| Never | 382 (74 %) | 78 (42 %) | 304 (92 %) | |
| Once a week or less | 77 (15 %) | 54 (29 %) | 23 (7 %) | |
| 2–6 times per week | 48 (9 %) | 44 (24 %) | 4 (1 %) | |
| Everyday | 11 (2 %) | 11 (6 %) | 0 (0 %) | |
| Lifetime duration of breastfeeding (N, %) | <0.0001 | |||
| >5 years | 151 (30 %) | 89 (49 %) | 62 (19 %) | |
| 2–5 years | 252 (49 %) | 60 (33 %) | 192 (59 %) | |
| <2 years | 107 (21 %) | 33 (18 %) | 74 (23 %) | |
| Contraceptive methods ever useda (N, %) | ||||
| Medroxyprogresterone acetate injectable | 367 (71 %) | 149 (80 %) | 218 (66 %) | 0.0006 |
| Oral contraceptives | 420 (81 %) | 100 (54 %) | 320 (97 %) | <0.0001 |
| Implant | 139 (27 %) | 12 (6 %) | 127 (38 %) | <0.0001 |
| Duration of contraceptive method use among all participants (months) | ||||
| Medroxyprogresterone acetate injectable | 3 (0, 24) | 15 (1, 37) | 0 (0, 12) | <0.0001 |
| Oral contraceptives | 29.5 (2.0, 72.0) | 1 (0, 14) | 51 (24, 84) | <0.0001 |
| Implantb | 0 (0, 0) | 0 (0, 0) | 0 (0, 0) | 0.0002 |
| Duration of contraceptive method use among participants indicating method use (months) | ||||
| Medroxyprogresterone acetate injectable | 12 (1, 36) | 24 (12, 48) | 6 (0, 28) | <0.0001 |
| Oral contraceptives | 38.5 (18.0, 84.0) | 12.5 (3, 33) | 53.5 (25, 87) | <0.0001 |
| Implant | 0.5 (0, 11) | 14 (1, 36) | 0 (0, 7) | 0.0011 |
| Physical Activity (total MET, hours/week) | 57.9 (29.4, 107.0) | 48.8 (23.7, 107.0) | 63.1 (32.6, 107.1) | 0.051 |
| Categorical physical activity score (N, %) | 0.068 | |||
| Low | 29 (6 %) | 14 (7 %) | 15 (5 %) | |
| Moderate | 166 (32 %) | 68 (36 %) | 98 (30 %) | |
| High | 323 (62 %) | 105 (56 %) | 218 (66 %) | |
| Total daily calcium (g) | 0.368 (0.243, 0.568) | 0.330 (0.189, 0.553) | 0.384 (0.273,0.574) | 0.0009 |
| Serum vitamin D concentration (ng/mL) | 30 (25, 35) | 28 (23, 32) | 31 (26, 36) | <0.0001 |
| Serum vitamin D concentration (N, %) | <0.0001 | |||
| Sufficient (>30 mg/mL) | 259 (50 %) | 71 (38 %) | 188 (57 %) | |
| Insufficient (20–29 mg/mL) | 236 (46 %) | 101 (54 %) | 135 (41 %) | |
| Deficient (0–19 ng/mL) | 22 (4 %) | 14 (8 %) | 8 (2 %) | |
| BMD lumbar spine (g/cm2) | 0.97 (0.90, 1.04) | 0.93 (0.88, 1.01) | 1.00 (0.92, 1.05) | <0.0001 |
| BMD total hip (g/cm2) | 0.96 (0.88, 1.03) | 0.93 (0.86, 0.99) | 0.98 (0.91, 1.05) | <0.0001 |
Median (interquartile range), unless indicated p values from chi-squared test for categorical variables and from Wilcoxon two-sample test for continuous variables
a
Percent of women reporting history of specific method
b
The mean duration of implant use among all participants is higher in Zimbabwe (3.8 months, standard deviation 13.6) than in Uganda (1.3 months, 7.2)