Table 3.

Multivariable-adjusted* relative risk (95% CI) of breast cancer according to quintiles of erythrocyte fatty acid concentration, Nurses’ Health Study II

	Quintiles of erythrocyte fatty acid concentrations
	Q1	Q2	Q3	Q4	Q5	ptrend
Total Saturated Fatty Acids	1.0 (ref)	0.75 (0.53–1.06)	0.89 (0.63–1.25)	0.61 (0.43–0.89)	0.85 (0.60–1.21)	0.47
Lauric acid (12:0)	1.0 (ref)	0.78 (0.54–1.14)	1.12 (0.77–1.63)	0.80 (0.54–1.18)	0.86 (0.58–1.29)	0.48
Mystristic acid (14:0)	1.0 (ref)	0.83 (0.60–1.16)	0.80 (0.57–1.14)	0.79 (0.56–1.12)	0.91 (0.63–1.31)	0.80
Pentadecanoic acid (15:0)	1.0 (ref)	1.21 (0.87–1.69)	0.91 (0.64–1.29)	1.07 (0.76–1.51)	1.08 (0.76–1.54)	0.95
Palmitic acid (16:0)	1.0 (ref)	0.98 (0.69–1.39)	1.02 (0.71–1.46)	0.79 (0.53–1.17)	0.79 (0.51–1.22)	0.19
Margric acid (17:0)	1.0 (ref)	1.23 (0.87–1.74)	1.09 (0.78–1.53)	1.13 (0.80–1.60)	1.13 (0.80–1.61)	0.75
Stearic acid (18:0)	1.0 (ref)	1.21 (0.85–1.71)	1.16 (0.82–1.64)	0.83 (0.57–1.19)	1.15 (0.80–1.64)	0.94
Nonadecanoic acid(19:0)	1.0 (ref)	1.16 (0.83–1.63)	1.23 (0.87–1.73)	1.05 (0.74–1.50)	1.18 (0.81–1.71)	0.57
Arachidic acid (20:0)	1.0 (ref)	1.18 (0.85–1.64)	0.98 (0.70–1.38)	1.07 (0.75–1.51)	1.08 (0.75–1.55)	0.89
Behenic acid (22:0)	1.0 (ref)	1.30 (0.92–1.84)	1.34 (0.93–1.93)	1.15 (0.78–1.69)	1.17 (0.77–1.77)	0.81
Tricosanoic acid (23:0)	1.0 (ref)	1.01 (0.72–1.43)	0.96 (0.66–1.42)	0.91 (0.61–1.35)	1.10 (0.71–1.70)	0.81
Lignoceric acid (24:0)	1.0 (ref)	1.00 (0.70–1.44)	1.05 (0.71–1.55)	0.88 (0.58–1.35)	0.83 (0.52–1.33)	0.34
Total Monounsaturated Fatty Acids	1.0 (ref)	0.87 (0.63–1.21)	0.99 (0.70–1.39)	0.82 (0.57–1.16)	0.91 (0.64–1.30)	0.56
Mysristoleic acid (14: 1n-5c)	1.0 (ref)	0.88 (0.63–1.24)	0.81 (0.58–1.15)	0.88 (0.62–1.26)	0.82 (0.57–1.18)	0.42
Pentadecenoic acid (15: 1n-5c)	1.0 (ref)	0.92 (0.66–1.29)	1.16 (0.83–1.62)	0.96 (0.68–1.35)	1.06 (0.74–1.51)	0.70
Palmitoleic acid (16: 1n-7c)	1.0 (ref)	0.91 (0.65–1.26)	0.70 (0.49–1.00)	0.85 (0.60–1.21)	0.72 (0.49–1.04)	0.13
Oleic acid (18: 1n-9c)	1.0 (ref)	1.05 (0.76–1.44)	0.93 (0.67–1.30)	0.78 (0.55–1.10)	0.93 (0.66–1.31)	0.37
Octadecenoic acid (18: 1n-7c)	1.0 (ref)	0.85 (0.61–1.19)	0.91 (0.65–1.27)	1.06 (0.76–1.47)	1.00 (0.71–1.40)	0.64
Gondoic acid (20: 1n-9c)	1.0 (ref)	1.10 (0.79–1.55)	1.16 (0.82–1.65)	1.19 (0.83–1.69)	1.36 (0.95–1.94)	0.09
Nervonic acid (24: 1n-9c)	1.0 (ref)	1.22 (0.88–1.68)	0.99 (0.69–1.42)	1.08 (0.75–1.56)	1.06 (0.70–1.61)	0.86
n-3 Polyunsaturated Fatty Acids	1.0 (ref)	1.07 (0.78–1.49)	0.86 (0.62–1.20)	0.82 (0.58–1.16)	1.02 (0.72–1.44)	0.75
Alpha-linolenic acid (ALA, 18: 3n-3c)	1.0 (ref)	0.70 (0.50–0.98)	0.84 (0.61–1.17)	0.76 (0.54–1.05)	0.82 (0.58–1.16)	0.37
Eicosapentaenoic acid (EPA,20:5n-3c)	1.0 (ref)	1.23 (0.88–1.71)	1.04 (0.74–1.46)	1.03 (0.73–1.46)	1.00 (0.71–1.43)	0.62
Docosapentaenoic acid (DPA,22:5n-3c)	1.0 (ref)	0.80 (0.58–1.10)	0.84 (0.60–1.17)	0.74 (0.52–1.05)	0.71 (0.49–1.03)	0.07
Docosahexaenoic acid (DHA, 22:6n-3c)	1.0 (ref)	1.04 (0.75–1.45)	0.88 (0.63–1.24)	1.00 (0.71–1.40)	1.10 (0.78–1.54)	0.62
n-6 Polyunsaturated Fatty Acids	1.0 (ref)	0.80 (0.57–1.13)	1.05 (0.76–1.46)	1.25 (0.91–1.72)	0.98 (0.69–1.40)	0.33
Linoleic acid (18:2n-6cc)	1.0 (ref)	1.12 (0.80–1.56)	1.05 (0.75–1.47)	1.24 (0.88–1.74)	1.24 (0.88–1.75)	0.19
Gamma-linolenic acid (18:3n-6c)	1.0 (ref)	1.04 (0.76–1.42)	0.75 (0.54–1.06)	0.85 (0.61–1.19)	0.76 (0.54–1.07)	0.08
Eicosadienoic acid (20:2n-6c)	1.0 (ref)	1.08 (0.77–1.52)	0.71 (0.50–1.03)	0.80 (0.56–1.14)	1.09 (0.75–1.58)	1.00
Dihomogammalinolenic acid (20:3n-6c)	1.0 (ref)	1.18 (0.85–1.63)	1.02 (0.73–1.42)	1.02 (0.72–1.43)	1.13 (0.80–1.60)	0.76
Arachidonic acid (20:4n-6c)	1.0 (ref)	0.91 (0.66–1.26)	0.86 (0.62–1.19)	1.13 (0.81–1.57)	0.81 (0.58–1.14)	0.51
Docosadienoic acid (22:2n-6c)	1.0 (ref)	1.07 (0.77–1.50)	1.03 (0.72–1.46)	1.21 (0.86–1.71)	1.20 (0.83–1.73)	0.25
Aolrenic acid (22:4n-6c)	1.0 (ref)	1.00 (0.71–1.41)	1.07 (0.77–1.49)	1.40 (0.99–1.96)	1.01 (0.69–1.47)	0.35
Total Trans Fatty Acids	1.0 (ref)	0.99 (0.72–1.38)	1.09 (0.78–1.53)	1.14 (0.81–1.60)	1.30 (0.92–1.84)	0.08
Palmitelaidic acid (16:1n-7t)	1.0 (ref)	0.92 (0.66–1.29)	1.20 (0.86–1.66)	1.07 (0.77–1.49)	1.12 (0.78–1.60)	0.40
Linolelaidic acid (18:2n-6t)	1.0 (ref)	1.05 (0.75–1.46)	0.99 (0.70–1.38)	1.07 (0.76–1.51)	1.02 (0.70–1.49)	0.89
Octadecadienoic acid (18:2n-7c)	1.0 (ref)	1.46 (1.02–2.09)	1.32 (0.88–1.98)	1.18 (0.78–1.78)	1.17 (0.75–1.83)	0.85
18:1 trans	1.0 (ref)	0.96 (0.69–1.34)	1.09 (0.78–1.53)	1.10 (0.78–1.55)	1.32 (0.94–1.86)	0.07
18:2 trans	1.0 (ref)	0.95 (0.68–1.31)	1.01 (0.73–1.40)	1.05 (0.76–1.47)	0.81 (0.57–1.15)	0.40
Dairy-derived Fatty Acidsa	1.0 (ref)	1.13 (0.81–1.60)	1.12 (0.79–1.57)	1.12 (0.80–1.57)	1.21 (0.85–1.71)	0.37
Industrial transb	1.0 (ref)	1.05 (0.75–1.45)	1.19 (0.85–1.65)	1.25 (0.89–1.77)	1.21 (0.85–1.72)	0.19
Total n-6/n-3 Ratio	1.0 (ref)	0.88 (0.63–1.24)	1.08 (0.78–1.52)	1.00 (0.71–1.42)	1.09 (0.78–1.55)	0.45
SI ration-7c	1.0 (ref)	1.04 (0.74–1.46)	0.97 (0.68–1.38)	1.06 (0.74–1.52)	1.32 (0.91–1.92)	0.13
SI ration-9d	1.0 (ref)	1.05 (0.75–1.47)	0.93 (0.66–1.31)	1.04 (0.73–1.47)	1.05 (0.75–1.49)	0.75

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