Table 4.
Associations between pregnancy-related nausea and vomiting and breast cancer risk among premenopausal women, stratified on time since last pregnancy.
| Time since last pregnancy | p-interaction | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
|
|
||||||||||
| < 5years | 5-10 years | > 10years | ||||||||
|
| ||||||||||
| Pregnancy-related Characteristic |
Cases, n=36 N (%) |
Controls, n=60 N (%) |
Multivariable- adjusted OR (95% CI)2 |
Cases, n=44 N (%) |
Controls, n=95 N (%) |
Multivariable- adjusted OR (95% CI)2 |
Cases, n=176 N (%) |
Controls, n=329 N (%) |
Multivariable- adjusted OR (95% CI)2 |
|
| Nausea and vomiting |
||||||||||
| Never | 12 (33.3) | 8 (13.3) | 1.00 reference | 8 (18.2) | 18 (19.0) | 1.00 reference | 38 (21.6) | 55 (16.7) | 1.00 reference | 0.14 |
| Ever | 24 (66.7) | 52 (86.7) | 0.22 (0.07-0.70) | 36 (81.8) | 77 (81.1) | 1.11 (0.39-3.13) | 138 (78.4) | 274 (83.3) | 0.62 (0.37-1.04) | |
| Severity of nausea and vomiting3 | ||||||||||
| Never | 12 (33.3) | 8 (13.3) | 1.00 reference | 8 (18.2) | 18 (19.0) | 1.00 reference | 38 (21.6) | 55 (16.7) | 1.00 reference | 0.08 |
| >0 to ≥1.0 | 14 (38.9) | 16 (26.7) | 0.36 (0.09-1.44) | 7 (15.9) | 30 (31.6) | 0.62 (0.18-2.19) | 49 (27.8) | 88 (26.8) | 0.69 (0.38-1.26) | |
| >1.0 | 10 (27.8) | 36 (60.0) | 0.16 (0.04-0.58) | 29 (65.9) | 47 (49.5) | 1.48 (0.50-4.40) | 89 (50.6) | 186 (56.5) | 0.59 (0.35-1.02) | |
| P-trend < 0.01 | P-trend = 0.26 | P-trend = 0.06 | ||||||||
| Duration of nausea and vomiting | ||||||||||
| Never | 12 (33.3) | 8 (13.3) | 1.00 reference | 8 (18.2) | 18 (19.0) | 1.00 reference | 38 (21.6) | 55 (16.7) | 1.00 reference | 0.06 |
| 1st trimester | 21 (58.3) | 32 (53.3) | 0.29 (0.09-1.00) | 22 (50.0) | 47 (49.5) | 1.35 (0.41-4.46) | 101 (57.4) | 188 (57.1) | 0.65 (0.38-1.11) | |
| 2nd-3rd trimesters |
3 (8.3) | 20 (33.3) | 0.11 (0.02-0.54) | 14 (31.8) | 30 (31.6) | 1.09 (0.96-1.24) | 37 (21.0) | 86 (26.1) | 0.56 (0.30-1.05) | |
| P-trend < 0.01 | P-trend = 0.58 | P-trend = 0.08 | ||||||||
| Proportion of pregnancies, %4 | ||||||||||
| Never | 7 (30.4) | 5 (11.4) | 1.00 reference | 3 (11.1) | 8 (12.7) | 1.00 reference | 14 (15.7) | 20 (12.2) | 1.00 reference | 0.01 |
| >0 to 49 | 7 (30.4) | 5 (11.4) | 0.87 (0.12-6.31) | 5 (18.5) | 15 (23.8) | 1.21 (0.17-8.48) | 13 (14.6) | 26 (15.9) | 0.66 (0.23-1.85) | |
| 50 to 75 | 7 (30.4) | 14 (31.8) | 0.13 (0.02-0.91) | 11 (40.7) | 23 (36.5) | 1.65 (0.30-8.98) | 23 (25.8) | 55 (33.5) | 0.46 (0.18-1.13) | |
| >75 | 2 (8.7) | 20 (45.5) | 0.05 (<0.01-0.38) | 8 (29.6) | 17 (27.0) | 0.80 (0.14-4.63) | 39 (43.8) | 63 (38.4) | 0.70 (0.30-1.66) | |
| P-trend < 0.01 | P-trend = 0.80 | P-trend = 0.53 | ||||||||
1
Excludes 5-10 year category
2
Adjusted for age, education, history of benign breast disease, family history of breast cancer, age at first pregnancy, number of pregnancies, menopausal status and age at menopause (among postmenopausal women)
3
Arbitrary units from subjective scale of severity ranging from 1 (minimal nausea) to 5 (severe nausea)
4
Restricted to women who had ≥3 pregnancies