Table 3.
Relative risk (RR) and 95% confidence intervals (95%CI) for breast cancer according to quintile of adolescent energy-adjusted carbohydrate quality and quantity, insulin index and insulin load among women in the Nurses’ Health Study II
| Quintile of intake | ||||||
|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | Ptrend | |
| Carbohydrate | ||||||
| All cases | ||||||
| Median intake, E% | 38.2 | 42.4 | 45.1 | 47.9 | 52.2 | |
| No. of cases/person-years | 236/120,472 | 247/120,546 | 242/120,661 | 203/120,694 | 207/120,507 | |
| Age-adjusted RR (95%CI) | 1 | 1.10 (0.92–1.31) | 1.09 (0.91–1.31) | 0.94 (0.77–1.13) | 0.99 (0.82–1.19) | 0.50 |
| Multivariable RR (95%CI) | 1 | 1.07 (0.90–1.28) | 1.08 (0.90–1.29) | 0.91 (0.75–1.10) | 0.97 (0.80–1.17) | 0.36 |
| Premenopausal cases | ||||||
| Median intake, E% | 38.4 | 42.5 | 45.3 | 48.1 | 52.3 | |
| No. of cases/person-years | 126/67,602 | 133/67,736 | 104/67,812 | 95/67,881 | 89/67,714 | |
| Age-adjusted RR (95%CI) | 1 | 1.10 (0.86–1.41) | 0.89 (0.68–1.16) | 0.83 (0.63–1.09) | 0.82 (0.62–1.08) | 0.04 |
| Multivariable RR (95%CI) | 1 | 1.09 (0.85–1.40) | 0.89 (0.68–1.16) | 0.83 (0.63–1.09) | 0.79 (0.60–1.04) | 0.02 |
| Postmenopausal cases | ||||||
| Median intake, E% | 37.6 | 41.8 | 44.6 | 47.3 | 51.6 | |
| No. of cases/person-years | 102/43,314 | 89/43,226 | 98/43,276 | 94/43,059 | 100/43,130 | |
| Age-adjusted RR (95%CI) | 1 | 0.91 (0.68–1.21) | 1.01 (0.77–1.34) | 0.98 (0.74–1.31) | 1.06 (0.80–1.40) | 0.56 |
| Multivariable RR (95%CI) | 1 | 0.89 (0.66–1.18) | 1.01 (0.76–1.34) | 0.96 (0.72–1.28) | 1.06 (0.80–1.41) | 0.59 |
| Glycemic index | ||||||
| All cases | ||||||
| Median intake/day | 51.6 | 53.6 | 55.0 | 56.3 | 58.4 | |
| No. of cases/person-years | 230/120,392 | 265/120,775 | 194/120,868 | 212/120,298 | 234/120,548 | |
| Age-adjusted RR (95%CI) | 1 | 1.17 (0.98–1.40) | 0.86 (0.70–1.04) | 0.97 (0.80–1.17) | 1.11 (0.92–1.33) | 0.84 |
| Multivariable RR (95%CI) | 1 | 1.18 (0.98–1.40) | 0.87 (0.72–1.06) | 0.99 (0.82–1.20) | 1.15 (0.95–1.38) | 0.54 |
| Premenopausal cases | ||||||
| Median intake/day | 51.6 | 53.6 | 54.9 | 56.3 | 58.4 | |
| No. of cases/person-years | 109/67,681 | 133/67,797 | 91/67,810 | 111/67,615 | 103/67,842 | |
| Age-adjusted RR (95%CI) | 1 | 1.26 (0.97–1.63) | 0.87 (0.65–1.15) | 1.12 (0.86–1.47) | 1.10 (0.84–1.44) | 0.77 |
| Multivariable RR (95%CI) | 1 | 1.28 (0.99–1.66) | 0.90 (0.68–1.19) | 1.15 (0.88–1.50) | 1.12 (0.85–1.47) | 0.68 |
| Postmenopausal cases | ||||||
| Median intake/day | 51.5 | 53.6 | 54.9 | 56.2 | 58.3 | |
| No. of cases/person-years | 102/43,268 | 104/43,185 | 87/43,260 | 85/43,198 | 105/43,094 | |
| Age-adjusted RR (95%CI) | 1 | 1.02 (0.78–1.35) | 0.87 (0.65–1.15) | 0.86 (0.64–1.14) | 1.10 (0.83–1.45) | 0.85 |
| Multivariable RR (95%CI) | 1 | 1.02 (0.77–1.34) | 0.88 (0.66–1.18) | 0.86 (0.65–1.16) | 1.13 (0.86–1.50) | 0.69 |
| Glycemic load | ||||||
| All cases | ||||||
| Median intake/day | 141 | 158 | 170 | 182 | 203 | |
| No. of cases/person-years | 240/122,851 | 256/119,561 | 206/115,371 | 228/126,140 | 205/118,956 | |
| Age-adjusted RR (95%CI) | 1 | 1.14 (0.96–1.37) | 0.97 (0.80–1.17) | 1.01 (0.84–1.22) | 1.01 (0.83–1.22) | 0.67 |
| Multivariable RR (95%CI) | 1 | 1.14 (0.96–1.37) | 0.97 (0.80–1.17) | 1.00 (0.83–1.20) | 1.01 (0.83–1.22) | 0.65 |
| Premenopausal cases | ||||||
| Median intake/day | 142 | 158 | 170 | 183 | 203 | |
| No. of cases/person-years | 117/68,024 | 130/67,438 | 116/67,702 | 95/67,731 | 89/67,851 | |
| Age-adjusted RR (95%CI) | 1 | 1.18 (0.92–1.52) | 1.10 (0.85–1.42) | 0.92 (0.70–1.21) | 0.92 (0.69–1.22) | 0.23 |
| Multivariable RR (95%CI) | 1 | 1.19 (0.92–1.53) | 1.10 (0.85–1.43) | 0.92 (0.70–1.22) | 0.90 (0.68–1.20) | 0.19 |
| Postmenopausal cases | ||||||
| Median intake/day | 139 | 156 | 168 | 180 | 200 | |
| No. of cases/person-years | 102/43,266 | 103/42,830 | 81/43,553 | 92/43,554 | 105/42,802 | |
| Age-adjusted RR (95%CI) | 1 | 1.05 (0.80–1.38) | 0.83 (0.61–1.11) | 0.94 (0.71–1.25) | 1.14 (0.86–1.50) | 0.56 |
| Multivariable RR (95%CI) | 1 | 1.04 (0.79–1.37) | 0.82 (0.61–1.11) | 0.92 (0.69–1.23) | 1.15 (0.87–1.52) | 0.52 |
| Dietary insulin index | ||||||
| All cases | ||||||
| Median intake/day | 39.8 | 42.0 | 43.6 | 45.1 | 47.4 | |
| No. of cases/person-years | 265/120,307 | 239/120,559 | 219/120,628 | 222/120,646 | 190/120,740 | |
| Age-adjusted RR (95%CI) | 1 | 0.94 (0.79–1.12) | 0.91 (0.76–1.09) | 0.93 (0.78–1.12) | 0.86 (0.71–1.04) | 0.13 |
| Multivariable RR (95%CI) | 1 | 0.96 (0.80–1.14) | 0.92 (0.77–1.10) | 0.95 (0.79–1.14) | 0.88 (0.73–1.06) | 0.21 |
| Premenopausal cases | ||||||
| Median intake/day | 39.9 | 42.2 | 43.7 | 45.2 | 47.5 | |
| No. of cases/person-years | 139/67,654 | 109/67,902 | 117/67,564 | 88/67,871 | 94/67,754 | |
| Age-adjusted RR (95%CI) | 1 | 0.85 (0.66–1.10) | 0.96 (0.75–1.23) | 0.72 (0.55–0.94) | 0.85 (0.65–1.11) | 0.11 |
| Multivariable RR (95%CI) | 1 | 0.86 (0.67–1.12) | 0.98 (0.76–1.26) | 0.73 (0.55–0.96) | 0.86 (0.66–1.13) | 0.14 |
| Postmenopausal cases | ||||||
| Median intake/day | 39.5 | 41.6 | 43.1 | 44.6 | 46.9 | |
| No. of cases/person-years | 104/43,199 | 109/43,191 | 91/43,153 | 95/43,200 | 84/43,263 | |
| Age-adjusted RR (95%CI) | 1 | 1.07 (0.81–1.40) | 0.93 (0.70–1.24) | 1.00 (0.75–1.32) | 0.90 (0.67–1.21) | 0.42 |
| Multivariable RR (95%CI) | 1 | 1.11 (0.84–1.46) | 0.95 (0.72–1.27) | 1.03 (0.78–1.37) | 0.95 (0.70–1.27) | 0.62 |
| Insulin load | ||||||
| All cases | ||||||
| Median intake/day | 1099 | 1160 | 1202 | 1244 | 1307 | |
| No. of cases/person-years | 267/120,427 | 236/120,399 | 217/121,288 | 222/120,179 | 193/120,588 | |
| Age-adjusted RR (95%CI) | 1 | 0.92 (0.77–1.10) | 0.88 (0.74–1.06) | 0.92 (0.77–1.11) | 0.86 (0.71–1.04) | 0.14 |
| Multivariable RR (95%CI) | 1 | 0.93 (0.78–1.11) | 0.89 (0.74–1.07) | 0.94 (0.78–1.12) | 0.88 (0.72–1.06) | 0.21 |
| Premenopausal cases | ||||||
| Median intake/day | 1102 | 1163 | 1205 | 1247 | 1310 | |
| No. of cases/person-years | 138/67,630 | 111/67,388 | 108/68,108 | 100/67,985 | 90/67,635 | |
| Age-adjusted RR (95%CI) | 1 | 0.86 (0.67–1.11) | 0.88 (0.68–1.14) | 0.81 (0.62–1.05) | 0.81 (0.62–1.07) | 0.10 |
| Multivariable RR (95%CI) | 1 | 0.88 (0.68–1.14) | 0.90 (0.69–1.16) | 0.82 (0.63–1.07) | 0.82 (0.63–1.08) | 0.12 |
| Postmenopausal cases | ||||||
| Median intake/day | 1090 | 1149 | 1190 | 1231 | 1295 | |
| No. of cases/person-years | 102/43,111 | 107/43,378 | 94/43,048 | 92/43,300 | 88/43,167 | |
| Age-adjusted RR (95%CI) | 1 | 1.07 (0.81–1.41) | 0.98 (0.74–1.30) | 0.98 (0.74–1.31) | 0.97 (0.73–1.30) | 0.69 |
| Multivariable RR (95%CI) | 1 | 1.10 (0.84–1.45) | 1.00 (0.75–1.33) | 1.02 (0.76–1.36) | 1.01 (0.76–1.36) | 0.90 |
Ptrend calculated with median intake of each variable in each quintile as a continuous variable.
Multivariable model was stratified by age in months at start of follow-up and calendar year of the current questionnaire cycle and was simultaneously adjusted for smoking (never, past, current 1–14/day, current 15–24/day, current ≥25/day), race (white/non-white), parity and age at first birth (nulliparous, parity ≤2 and age at first birth <25 years, parity≤2 and age at first birth 25–<30 years, parity ≤2 and age at first birth ≥30 years, parity 3–4 and age at first birth <25 years, parity 3–4 and age at first birth 25–<30 years, parity 3–4 and age at first birth ≥30 years, parity ≥5 and age at first birth <25 years, parity ≥5 and age at first birth ≥25 years), height (<62, 62–<65, 65–<68, ≥68 inches), BMI at age 18 years (<18.5, 18.5 to <20.0, 20.0 to <22.5, 22.5 to <25.0, 25.0 to <30.0, ≥30.0 kg/m2), weight gain since age 18 (≤−5, >−5–5, >5–10, >10–20, >20 kg), age at menarche (<12, 12, 13, ≥14 years), family history of breast cancer (yes, no), history of benign breast disease (yes, no), oral contraceptive use (never, past, current), menopausal status (premenopausal, postmenopausal, dubious), hormone use (postmenopausal never users, postmenopausal past users, postmenopausal current users), age at menopause (continuous), adolescent alcohol intake (nondrinker, <1.5, 1.5–<5, 5–<10, ≥10 g/day), adult alcohol intake (nondrinker, <5, 5–<15,≥15 g/day), adolescent energy intake (quintile).