Table 4.

Multivariable analysis of breast cancer by weekly fish and fish liver oil consumption

IR per 1,000 person yearsAge-adjusted HR (95% CI)HRa (95% CI)HRb (95% CI)
Adolescence (14–19 years)a
 Fish consumptionn = 91n = 90n = 88
  ≤2 portions4.041.00 (Ref.)1.00 (Ref.)1.00 (Ref.)
  >2 up to 4 portions4.441.09 (0.57–1.20)1.13 (0.59–2.17)1.19 (0.61–2.31)
  >4 portions3.210.79 (0.51–1.25)0.74 (0.47–1.17)0.71 (0.44–1.13)
 Fish liver oil consumption
  Never3.621.00 (Ref.)1.00 (Ref.)1.00 (Ref.)
  Daily or less3.881.07 (0.71–1.62)1.07 (0.70–1.63)1.10 (0.71–1.69)
Midlife (40–50 years)b
 Fish consumptionn = 91n = 90n = 90
  ≤2 portions5.051.00 (Ref.)1.00 (Ref.)1.00 (Ref.)
  >2 up to 4 portions4.070.80 (0.44–1.42)0.82 (0.46–1.48)0.81 (0.45–1.47)
  >4 portions4.070.47 (0.23–0.99)0.47 (0.23–0.99)0.46 (0.22–0.97)
 Fish liver oil consumption
  Never3.901.00 (Ref.)1.00 (Ref.)1.00 (Ref.)
  Daily or less3.700.95 (0.61–1.46)0.97 (0.62–1.51)0.96 (0.62–1.49)
Late life (66–96 years)c
 Fish liver oil consumptionn = 91n = 88n = 88
  Never3.051.00 (Ref.)1.00 (Ref.)1.00 (Ref.)
  Daily or less4.051.34 (0.81–2.22)1.33 (0.81–2.20)1.31 (0.79–2.16)
  • NOTE: All portions are based on weekly consumption.

  • Abbreviations: CI, confidence interval; n, number of breast cancer diagnoses in analysis.

  • aAdolescence: HRa adjusted for age upon entry, education, family history of breast cancer, BMI in midlife, age at first child and age at menarche. HRb additionally adjusted for intake of milk, rye, meat, fish liver oil (in fish analyses), salted/smoked fish in adolescence and fish (for fish liver oil analyses).

  • bMidlife: HRa adjusted for same covariates as in HR in adolescence plus use of alcohol in midlife. HRb Additionally adjusted for same food items as in adolescence, replaced with midlife values.

  • cLate life: HRa adjusted for same covariates as in midlife except values for body mass index and alcohol consumption in late life were replaced for midlife values.HRb additionally adjusted for same food items as in midlife and adolescence, replaced with late life values.