Table 4.

Multivariable-adjusted* relative risk (95% CI) of breast cancer according to quartiles of erythrocyte fatty acid concentration, stratified by BMI at blood collection, Nurses’ Health Study II

	BMI < 25 kg/m2(max 468 cases/428 controls)					BMI ≥ 25 kg/m2 (max 325 cases/365 controls)
	Quartiles of erythrocyte fatty acid concentrations					Quartiles of erythrocyte fatty acid concentrations
	Q1	Q2	Q3	Q4	ptrend	Q1	Q2	Q3	Q4	ptrend	pint
Total Saturated Fatty Acids	1.0 (ref)	0.76 (0.52–1.12)	0.57 (0.39–0.84)	0.68 (0.46–0.98)	0.05	1.0 (ref)	0.91 (0.58–1.44)	1.11 (0.70–1.76)	1.41 (0.90–2.21)	0.07	0.01
Lauric acid (12:0)	1.0 (ref)	0.94 (0.65–1.38)	0.97 (0.66–1.42)	0.87 (0.59–1.28)	0.50	1.0 (ref)	0.85 (0.54–1.34)	0.95 (0.61–1.49)	0.92 (0.58–1.46)	0.92	0.69
Mystristic acid (14:0)	1.0 (ref)	0.76 (0.52–1.10)	0.75 (0.51–1.11)	0.87 (0.60–1.27)	0.65	1.0 (ref)	0.85 (0.53–1.38)	0.97 (0.62–1.53)	1.08 (0.68–1.70)	0.52	0.44
Pentadecanoic acid (15:0)	1.0 (ref)	1.13 (0.76–1.67)	0.76 (0.51–1.14)	0.81 (0.54–1.19)	0.11	1.0 (ref)	1.09 (0.70–1.71)	1.31 (0.84–2.05)	1.68 (1.07–2.64)	0.02	0.002
Palmitic acid (16:0)	1.0 (ref)	1.30 (0.90–1.89)	1.00 (0.68–1.46)	0.91 (0.61–1.37)	0.46	1.0 (ref)	0.78 (0.50–1.23)	0.96 (0.60–1.54)	0.86 (0.54–1.36)	0.71	0.80
Margric acid (17:0)	1.0 (ref)	1.12 (0.73–1.72)	0.74 (0.48–1.13)	0.78 (0.51–1.19)	0.08	1.0 (ref)	1.15 (0.75–1.76)	1.28 (0.80–2.04)	1.85 (1.18–2.88)	0.01	0.000
Stearic acid (18:0)	1.0 (ref)	0.96 (0.65–1.42)	0.78 (0.52–1.15)	0.72 (0.49–1.06)	0.06	1.0 (ref)	0.96 (0.60–1.52)	1.01 (0.65–1.58)	1.58 (1.01–2.47)	0.02	0.003
Nonadecanoic acid (19:0)	1.0 (ref)	1.25 (0.82–1.89)	0.91 (0.60–1.38)	0.78 (0.51–1.19)	0.08	1.0 (ref)	1.28 (0.84–1.97)	1.38 (0.88–2.17)	1.71 (1.05–2.78)	0.03	0.01
Arachidic acid (20:0)	1.0 (ref)	1.26 (0.84–1.91)	0.74 (0.49–1.12)	0.87 (0.58–1.32)	0.18	1.0 (ref)	0.99 (0.65–1.50)	1.23 (0.77–1.96)	1.53 (0.97–2.41)	0.05	0.02
Behenic acid (22:0)	1.0 (ref)	1.52 (1.03–2.25)	1.39 (0.93–2.08)	1.20 (0.81–1.79)	0.68	1.0 (ref)	0.90 (0.58–1.40)	0.80 (0.51–1.26)	1.05 (0.66–1.68)	0.88	0.87
Tricosanoic acid (23:0)	1.0 (ref)	1.14 (0.77–1.68)	1.02 (0.69–1.51)	1.24 (0.84–1.85)	0.37	1.0 (ref)	0.99 (0.63–1.56)	0.99 (0.64–1.56)	0.99 (0.64–1.55)	0.98	0.56
Lignoceric acid (24:0)	1.0 (ref)	1.20 (0.82–1.75)	1.16 (0.79–1.69)	0.91 (0.61–1.35)	0.60	1.0 (ref)	0.62 (0.39–0.98)	0.74 (0.47–1.16)	0.82 (0.52–1.27)	0.61	0.83
Total Monounsaturated Fatty Acids	1.0 (ref)	1.18 (0.82–1.70)	0.85 (0.58–1.24)	1.02 (0.67–1.54)	0.69	1.0 (ref)	0.83 (0.52–1.33)	0.80 (0.49–1.29)	0.68 (0.42–1.09)	0.12	0.25
Mysristoleic acid (14:1n-5c)	1.0 (ref)	0.78 (0.54–1.13)	0.70 (0.47–1.02)	0.77 (0.53–1.13)	0.20	1.0 (ref)	0.69 (0.43–1.12)	0.84 (0.52–1.34)	0.96 (0.60–1.51)	0.57	0.20
Pentadecenoic acid (15:1n-5c)	1.0 (ref)	1.58 (1.04–2.41)	1.18 (0.79–1.77)	1.10 (0.74–1.63)	0.88	1.0 (ref)	0.69 (0.45–1.06)	1.00 (0.64–1.56)	1.15 (0.71–1.85)	0.41	0.32
Palmitoleic acid (16: 1n-7c)	1.0 (ref)	0.74 (0.52–1.05)	0.70 (0.48–1.02)	0.83 (0.52–1.30)	0.38	1.0 (ref)	1.17 (0.70–1.96)	1.10 (0.67–1.81)	0.89 (0.54–1.47)	0.34	0.82
Oleic acid (18: 1n-9c)	1.0 (ref)	0.82 (0.57–1.19)	0.85 (0.58–1.25)	0.89 (0.60–1.32)	0.54	1.0 (ref)	0.69 (0.43–1.10)	0.63 (0.40–1.00)	0.67 (0.42–1.05)	0.08	0.30
Octadecenoic acid (18:1n-7c)	1.0 (ref)	0.87 (0.58–1.29)	1.29 (0.87–1.89)	0.94 (0.63–1.40)	0.89	1.0 (ref)	0.64 (0.41–1.02)	0.84 (0.55–1.31)	1.01 (0.65–1.58)	0.68	0.96
Gondoic acid (20: 1n-9c)	1.0 (ref)	0.97 (0.64–1.46)	1.01 (0.68–1.52)	1.14 (0.77–1.68)	0.44	1.0 (ref)	1.22 (0.79–1.90)	1.19 (0.76–1.87)	1.46 (0.92–2.31)	0.12	0.71
Nervonic acid (24: 1n-9c)	1.0 (ref)	0.79 (0.54–1.17)	0.95 (0.65–1.40)	0.98 (0.67–1.43)	0.87	1.0 (ref)	1.10 (0.70–1.73)	0.92 (0.59–1.45)	1.05 (0.66–1.65)	1.00	0.77
n-3 Polyunsaturated Fatty Acids	1.0 (ref)	1.32 (0.88–1.97)	1.03 (0.70–1.51)	1.11 (0.76–1.64)	0.87	1.0 (ref)	0.74 (0.48–1.13)	0.68 (0.43–1.07)	0.68 (0.42–1.08)	0.11	0.23
Alpha-linolenic acid (ALA, 18: 3n-3c)	1.0 (ref)	0.81 (0.55–1.19)	0.93 (0.63–1.37)	1.07 (0.72–1.59)	0.47	1.0 (ref)	0.76 (0.48–1.20)	0.76 (0.49–1.17)	0.57 (0.36–0.89)	0.02	0.03
Eicosapentaenoic acid (EPA,20:5n-3c)	1.0 (ref)	1.11 (0.76–1.63)	1.12 (0.76–1.64)	1.18 (0.79–1.75)	0.46	1.0 (ref)	0.82 (0.51–1.30)	0.84 (0.53–1.32)	0.56 (0.34–0.89)	0.02	0.04
Docosapentaenoic acid (DPA,22:5n-3c)	1.0 (ref)	0.89 (0.60–1.32)	0.72 (0.48–1.08)	0.85 (0.57–1.27)	0.34	1.0 (ref)	0.81 (0.53–1.24)	0.82 (0.53–1.28)	0.62 (0.39–0.98)	0.05	0.54
Docosahexaenoic acid (DHA, 22:6n-3c)	1.0 (ref)	1.25 (0.84–1.87)	1.16 (0.78–1.73)	1.31 (0.88–1.94)	0.26	1.0 (ref)	0.68 (0.44–1.06)	0.67 (0.43–1.05)	0.77 (0.49–1.23)	0.34	0.20
n-6 Polyunsaturated Fatty Acids	1.0 (ref)	0.84 (0.56–1.25)	1.18 (0.80–1.73)	1.29 (0.88–1.90)	0.10	1.0 (ref)	1.03 (0.66–1.61)	1.10 (0.71–1.70)	0.74 (0.46–1.18)	0.37	0.09
Linoleic acid (18:2n-6cc)	1.0 (ref)	1.24 (0.81–1.88)	1.36 (0.91–2.04)	1.65 (1.11–2.46)	0.01	1.0 (ref)	0.73 (0.48–1.13)	0.91 (0.58–1.42)	0.79 (0.51–1.24)	0.43	0.04
Gamma-linolenic acid (18:3n-6c)	1.0 (ref)	0.94 (0.66–1.34)	1.00 (0.69–1.46)	1.08 (0.71–1.63)	0.68	1.0 (ref)	1.17 (0.71–1.92)	0.88 (0.55–1.43)	0.62 (0.38–1.01)	0.01	0.05
Eicosadienoic acid (20:2n-6c)	1.0 (ref)	1.08 (0.73–1.60)	0.90 (0.61–1.35)	1.25 (0.85–1.84)	0.31	1.0 (ref)	0.78 (0.50–1.20)	0.77 (0.50–1.19)	0.80 (0.51–1.24)	0.32	0.15
Dihomogammalinolenic acid (20:3n-6c)	1.0 (ref)	1.01 (0.70–1.45)	1.10 (0.76–1.59)	0.94 (0.62–1.43)	0.92	1.0 (ref)	0.95 (0.58–1.55)	0.76 (0.46–1.24)	0.94 (0.59–1.50)	0.79	0.80
Arachidonic acid (20:4n-6c)	1.0 (ref)	0.99 (0.67–1.46)	1.15 (0.79–1.68)	0.98 (0.66–1.44)	0.89	1.0 (ref)	0.57 (0.36–0.90)	0.88 (0.57–1.36)	0.78 (0.50–1.21)	0.50	0.52
Docosadienoic acid (22:2n-6c)	1.0 (ref)	0.91 (0.61–1.36)	0.92 (0.61–1.39)	0.84 (0.57–1.25)	0.41	1.0 (ref)	1.44 (0.92–2.27)	1.44 (0.92–2.25)	2.23 (1.39–3.58)	0.00	0.01
Aolrenic acid (22:4n-6c)	1.0 (ref)	1.02 (0.70–1.50)	0.86 (0.58–1.27)	1.04 (0.70–1.55)	0.96	1.0 (ref)	0.98 (0.62–1.55)	1.32 (0.84–2.06)	1.16 (0.73–1.85)	0.35	0.56
Total Trans Fatty Acids	1.0 (ref)	0.83 (0.56–1.25)	1.06 (0.71–1.57)	0.91 (0.61–1.36)	0.89	1.0 (ref)	0.95 (0.59–1.51)	1.49 (0.94–2.36)	1.88 (1.17–3.03)	0.002	0.02
Palmitelaidic acid (16:1n-7t)	1.0 (ref)	1.08 (0.71–1.63)	1.24 (0.83–1.86)	0.87 (0.58–1.30)	0.48	1.0 (ref)	1.12 (0.71–1.77)	1.34 (0.85–2.12)	2.41 (1.50–3.89)	0.000	0.000
Linolelaidic acid (18:2n-6t)	1.0 (ref)	0.85 (0.58–1.26)	0.88 (0.61–1.29)	0.90 (0.61–1.33)	0.65	1.0 (ref)	0.99 (0.63–1.57)	1.41 (0.88–2.24)	1.18 (0.75–1.86)	0.33	0.24
Octadecadienoic acid (18:2n-7c)	1.0 (ref)	1.20 (0.82–1.74)	1.07 (0.73–1.56)	0.83 (0.55–1.24)	0.29	1.0 (ref)	1.30 (0.80–2.13)	1.28 (0.79–2.08)	1.49 (0.92–2.42)	0.14	0.10
18:1 trans	1.0 (ref)	0.73 (0.49–1.10)	1.00 (0.67–1.49)	0.91 (0.61–1.35)	0.98	1.0 (ref)	1.18 (0.75–1.87)	1.46 (0.92–2.33)	2.33 (1.45–3.77)	0.000	0.01
18:2 trans	1.0 (ref)	0.83 (0.57–1.21)	1.05 (0.71–1.53)	0.78 (0.52–1.15)	0.38	1.0 (ref)	0.78 (0.49–1.24)	0.75 (0.47–1.19)	0.81 (0.51–1.29)	0.42	0.95
Dairy-derived Fatty Acidsa	1.0 (ref)	0.91 (0.60–1.39)	0.88 (0.59–1.33)	0.72 (0.48–1.08)	0.09	1.0 (ref)	1.00 (0.64–1.55)	1.21 (0.77–1.89)	1.83 (1.16–2.89)	0.005	0.000
Industrial transb	1.0 (ref)	0.76 (0.50–1.13)	1.07 (0.71–1.59)	0.90 (0.61–1.34)	0.98	1.0 (ref)	0.84 (0.52–1.33)	1.31 (0.84–2.06)	1.86 (1.16–2.97)	0.003	0.02
Total n-6/n-3 Ratio	1.0 (ref)	0.92 (0.62–1.36)	1.15 (0.78–1.69)	1.09 (0.74–1.62)	0.49	1.0 (ref)	0.87 (0.55–1.39)	1.10 (0.69–1.74)	1.19 (0.74–1.91)	0.32	0.90
SI ration-7c	1.0 (ref)	0.77 (0.48–1.21)	0.88 (0.56–1.39)	1.09 (0.70–1.71)	0.23	1.0 (ref)	1.30 (0.86–1.98)	1.36 (0.87–2.14)	1.17 (0.70–1.94)	0.46	0.99
SI ration-9d	1.0 (ref)	0.91 (0.61–1.36)	0.74 (0.50–1.11)	0.80 (0.54–1.19)	0.23	1.0 (ref)	0.96 (0.62–1.48)	1.08 (0.68–1.72)	1.45 (0.93–2.27)	0.08	0.03

Adjusted for: age at menarche (<12, 13–14, 14+ years), age at first birth/parity (nulliparous, 1–2 children <25 years, 3+ children <25 years, 1–2 children >25 years, and 3+ children >25 years), lactation (yes/no), family history of breast cancer (yes/no), history of benign breast disease (yes/no), alcohol consumption(</>5 grams/day), BMI at age 18 (<21, 21–23 and >23 kg/m2), weight change between age 18 and blood collection(continuous), physical activity (<3, 3 to <9, 9 to <18, 18 to <27 and 27+ MET-hours/week)

^aDairy-derived fatty acids=15:0 + 17:0 + 16:1n-7t

^bIndustrial trans=18:1 trans+18:2 trans

^cSI ratio_n-7= Palmitic acid/Palmitoleic acid

^dSI ratio_n-9=Stearic acid/Oleic acid