Table 3.

Adjusted odds ratios (95% confidence intervals)  of colon and rectal cancer by quartile levels of plasma saturated and monounsaturated fatty acids (MUFA) and their desaturase indices, the Singapore Chinse Health Study^a 

	1st (low)	2nd	3rd	4th (high)	P trend
Colon cancer
Saturated fatty acids
Palmitic acid (16:0)	1.00 (Referent)	0.77 (0.40–1.49)	0.71 (0.37–1.36)	0.41 (0.20–0.83)	0.016
Stearic acid (18:0)	1.00 (Referent)	0.97 (0.55–1.69)	0.96 (0.56–1.64)	0.55 (0.30–0.99)	0.070
MUFAs
Palmitoleic acid (16:1)	1.00 (Referent)	0.79 (0.44–1.42)	0.81 (0.46–1.41)	0.51 (0.28–0.95)	0.051
Oleic acid (18:1)	1.00 (Referent)	0.56 (0.30–1.04)	0.69 (0.37–1.28)	0.39 (0.20–0.76)	0.015
Stearoyl-coenzyme A desaturase (SCD)-1 indices
Palmitoleic:Palmitic acid ratio	1.00 (Referent)	0.79 (0.43–1.44)	0.93 (0.54–1.59)	0.58 (0.31–1.08)	0.165
Oleic:Stearic acid ratio	1.00 (Referent)	0.79 (0.41–1.51)	0.58 (0.28–1.23)	0.42 (0.19–0.92)	0.024
Rectal cancer
Saturated fatty acids
Palmitic acid (16:0)	1.00 (Referent)	0.92 (0.46–1.83)	1.15 (0.55–2.44)	1.50 (0.65–3.44)	0.312
Stearic acid (18:0)	1.00 (Referent)	1.55 (0.78–3.09)	0.84 (0.39–1.82)	1.72 (0.79–3.75)	0.356
MUFAs
Palmitoleic acid (16:1)	1.00 (Referent)	0.81 (0.40–1.62)	0.98 (0.50–1.90)	1.10 (0.51–2.39)	0.768
Oleic acid (18:1)	1.00 (Referent)	1.70 (0.86–3.36)	1.43 (0.68–3.01)	1.77 (0.80–3.91)	0.219
SCD-1 indices
Palmitoleic:Palmitic acid ratio	1.00 (Referent)	0.90 (0.45–1.80)	1.12 (0.49–2.58)	1.09 (0.50–2.36)	0.743
Oleic:Stearic acid ratio	1.00 (Referent)	1.54 (0.76–3.12)	1.26 (0.62–2.58)	1.15 (0.48–2.76)	0.730

^a Odds ratios are adjusted for body mass index (<20, 20–24, 24–28, ≥28 kg/m²), smoking (never, light, heavy), education level (none, primary, ≥secondary), alcohol use (none, <7, ≥7 drinks/week), weekly physical activity (yes, no), history of diabetes (yes, no), and use of nonsteroidal anti-inflammatory drugs (NSAIDs) (yes, no)