Article Figures & Data
Tables
- Table 1.
Characteristics of 86,972 parous U.S. women in the NHS II cohort in 1989, by history of GDM
No history of GDM n = 81,784 History of GDM n = 5,188 Agea 35.0 ± 4.7 33.8 ± 4.4 Lifestyle factors BMI 23.9 ± 4.7 25.8 ± 5.9 Normal weight (BMI < 25.0), % 71 55 Overweight (BMI 25.0–29.9), % 18 25 Obese (BMI ≥ 30), % 10 20 BMI at age 18b 21.0 ± 3.0 21.5 ± 3.6 Normal weight at 18 (BMI < 25.0), % 91 87 Overweight/obese at 18 (BMI ≥ 25.0), % 8 12 Height (inches) 64.9 ± 2.6 64.5 ± 2.6 Total physical activity (MET-hrs/week) 23.7 ± 35.2 21.8 ± 33.0 Alternative Healthy Eating Index scoreb 47.9 (10.7) 47.2 (10.5) Fruit and vegetable intake (servings/day)b 4.2 ± 2.3 4.3 ± 2.5 Alcohol intake (g/day)b 2.9 ± 5.6 2.2 ± 4.8 Smoking total pack years 7.4 ± 60.7 6.9 ± 55.4 Smoking status, % Never 66 66 Past 22 21 Current smoker 12 13 Current multivitamin use, % 46 47 Other risk factors Age at menarche, % ≤10 years 7 10 11–12 years 46 48 13–14 years 38 35 ≥15 years 8 7 Regularity of menses at ages 18–22, % Regular or very regular 74 72 Usually or always irregular 22 25 Age at first birth (years) 26.5 ± 4.5 27.6 ± 5.0 Parity (pregnancies ≥6 months) 1.8 ± 1.1 1.8 ± 1.2 Birth indexc 16.1 (14.3) 14.3 (14.8) Total breastfeeding, %b None 15 13 <6 months 13 13 ≥6 months 46 43 Oral contraceptive use, % Never 15 16 Past 73 72 Current 12 12 History of pregnancy-induced hypertension 10 20 Mammography screening among women >40 years old, % <40 years old 80 80 ≥40 years old, with screening 11 11 ≥40 years old, no screening 5 5 ≥40 years old, mammography for symptoms 4 4 Hysterectomy 5 5 Bilateral oophorectomy 1 1 Family history of diabetes, % 14 28 Family history of breast cancer, % 6 5 Personal history of benign breast disease, %b 29 30 Race/ethnicity, % White 96 93 Black 2 3 Asian 2 3 NOTE: Values represent means ± SD unless otherwise indicated and are standardized to the age distribution of the study population. Values of categorical variables may not sum to 100% due to rounding.
↵aValue is not age adjusted.
↵bMissing data on BMI at age 18 in 1% of participants, food frequency and alcohol intake in 16.3% of participants, breastfeeding in 14.6% of parous participants, and history of benign breast disease in 3.6% of participants. All other data were missing in less than 1% of participants.
↵cBirth index was calculated by summing total years from each birth to current age (or age at menopause for postmenopausal women) over all births.
- Table 2.
Association between history of GDM and incident invasive breast cancer risk
No GDM GDM HR (95% CI) HR (95% CI) P Cases, no. 2,277 100 Person-yearsa 923,694 58,384 Age adjusted 1.00 (reference) 0.68 (0.55–0.84) 0.0003 Multivariable adjusted 1.00 (reference) 0.68 (0.55–0.84) 0.0004 NOTE: Multivariable model additionally adjusts for BMI at age 18 (continuous), weight gain since age 18 (continuous), height (continuous), total physical activity (MET-hours/week, quintiles), alcohol intake (none, 1–14 grams/day, ≥15 grams/day), age at menarche (≤10 years old, 11–12, 13–14, ≥15), birth index (continuous), total breastfeeding (none, <6 months, ≥6 months), menopausal status (premenopausal, postmenopausal, unknown), hormone therapy use (never, ever use of estrogen + progesterone, past: estrogen only or other, current: estrogen only or other), family history of breast cancer in mother or sister (yes/no), personal history of benign breast disease (yes/no), white race/ethnicity (yes/no), and mammography within the past 2 years (<40 years old, ≥40 and no mammography, ≥40 and mammography for screening, ≥40 and mammography for abnormality/symptoms).
↵aPerson-years are calculated as the time from age at first birth or first GDM pregnancy, through the end of follow-up (the date of incident breast cancer diagnosis, death, or last questionnaire return through May 31, 2013).
- Table 3.
Association between history of GDM and incident invasive breast cancer risk, stratified by risk factors
Cases, no. No GDM GDM Stratified by risk factors No GDM/GDM HR (95% CI) HR (95% CI) Pinteraction Current BMI category (kg/m2)a Normal (<25.0) 1,116/49 1.00 (reference) 0.97 (0.72–1.32) 0.04 Overweight (25.0–29.9) 646/25 1.00 (reference) 0.50 (0.32–0.78) Obese (≥30.0) 512/26 1.00 (reference) 0.50 (0.32–0.77) Age at first birth <30 years 1,707/59 1.00 (reference) 0.57 (0.39–0.83) 0.85 ≥30 years 570/41 1.00 (reference) 0.89 (0.64–1.24) Family history of breast cancer No 1,900/83 1.00 (reference) 0.65 (0.52–0.83) 0.96 Yes 377/17 1.00 (reference) 0.76 (0.44–1.31) Family history of diabetes No 1,669/62 1.00 (reference) 0.75 (0.57–0.98) 0.33 Yes 608/38 1.00 (reference) 0.59 (0.41–0.85) Physical activity Low (Q1–Q3) 1,457/58 1.00 (reference) 0.56 (0.42–0.74) 0.04 High (Q4–Q5) 820/42 1.00 (reference) 0.98 (0.70–1.37) Total lifetime breastfeeding None to <6 months 933/29 1.00 (reference) 0.55 (0.37–0.81) 0.08 ≥6 months 1,344/71 1.00 (reference) 0.77 (0.59–0.99) NOTE: Multivariable model adjusts for age, BMI at age 18 (continuous), weight gain since age 18 (continuous), height (continuous), total physical activity (MET-hours/week, quintiles), alcohol intake (none, 1–14 grams/day, ≥15 grams/day), age at menarche (≤10 years old, 11–12, 13–14, ≥15), birth index (continuous), total breastfeeding (none, <6 months, ≥6 months), menopausal status (premenopausal, postmenopausal, unknown), hormone therapy use (never, ever use of estrogen + progesterone, past: estrogen only or other, current: estrogen only or other), family history of breast cancer in mother or sister (yes/no), personal history of benign breast disease (yes/no), white race/ethnicity (yes/no), and mammography within the past 2 years (<40 years old, ≥40 and no mammography, ≥40 and mammography for screening, ≥40 and mammography for abnormality/symptoms).
↵aMultivariable model is adjusted for current BMI (continuous).
- Table 4.
Association between history of GDM and incident invasive breast cancer risk, by intermediate type II diabetes status
No GDM or type II diabetes GDM only Type II diabetes only Both GDM and type II diabetes HR (95% CI) HR (95% CI) HR (95% CI) HR (95% CI) All women Cases, no. 2,224 95 53 5 Person-years 907,823 53,635 20,576 5,982 Age adjusted 1.00 (reference) 0.72 (0.58–0.90) 0.63 (0.37–1.07) 0.23 (0.09–0.61) Multivariable model 1.00 (reference) 0.72 (0.58–0.89) 0.69 (0.40–1.18) 0.26 (0.10–0.68) NOTE: Multivariable model adjusts for age, BMI at age 18 (continuous), weight gain since age 18 (continuous), height (continuous), total physical activity (MET-hours/week, quintiles), alcohol intake (none, 1–14 grams/day, ≥15 grams/day), age at menarche (≤10 years old, 11–12, 13–14, ≥15), birth index (continuous), total breastfeeding (none, <6 months, ≥6 months), menopausal status (premenopausal, postmenopausal, unknown), hormone therapy use (never, ever use of estrogen + progesterone, past: estrogen only or other, current: estrogen only or other), family history of breast cancer in mother or sister (yes/no), personal history of benign breast disease (yes/no), white race/ethnicity (yes/no), and mammography within the past 2 years (<40 years old, ≥40 and no mammography, ≥40 and mammography for screening, ≥40 and mammography for abnormality/symptoms).
Volume 26, Issue 3
