TABLE 2.
Relative risks (RR) and 95% confidence intervals (95% CI) for basal cell carcinoma by ranked thirds of dietary intake of omega-3 and omega-6 fatty acids from food frequency questionnaire, person-based analysis in 1322 participants of the Nambour Skin Cancer Study, 1997–2007
| Ranked thirds of intake |
||||
|---|---|---|---|---|
| Fatty acids | Low n = 440 |
Middle n = 441 |
High n = 441 |
P for trenda |
| Sum of omega-3, g/dayb | <0.90 | 0.90–1.10 | >1.10 | |
| Number of cases, n | 109 | 99 | 117 | |
| Basic RR (95% CI)c | 1.00 | 0.89 (0.68–1.17) | 0.94 (0.72–1.23) | 0.67 |
| Multivariate RR (95% CI)d | 1.00 | 0.89 (0.68–1.18) | 0.91 (0.70–1.19) | 0.49 |
| Sum of long-chain omega-3, g/daye | <0.16 | 0.16–0.26 | >0.26 | |
| Number of cases, n | 10.4 | 110 | 104 | |
| Basic RR (95% CI) | 1.00 | 1.01 (0.77–1.32) | 0.89 (0.67–1.17) | 0.38 |
| Multivariate RR (95% CI) | 1.00 | 1.02 (0.77–1.33) | 0.88 (0.67–1.16) | 0.35 |
| α-Linolenic acid (18:3), g/day | <0.68 | 0.68–0.83 | >0.83 | |
| Number of cases, n | 112 | 99 | 114 | |
| Basic RR (95% CI) | 1.00 | 0.87 (0.67–1.14) | 0.96 (0.74–1.25) | 0.79 |
| Multivariate RR (95% CI) | 1.00 | 0.86 (0.66–1.14) | 0.93 (0.71–1.21) | 0.59 |
| EPA (20:5), g/day | <0.05 | 0.05–0.09 | >0.09 | |
| Number of cases, n | 103 | 115 | 107 | |
| Basic RR (95% CI) | 1.00 | 1.07 (0.82–1.40) | 0.92 (0.70–1.21) | 0.54 |
| Multivariate RR (95% CI) | 1.00 | 1.07 (0.82–1.40) | 0.91 (0.69–1.20) | 0.50 |
| DPA (22:5), g/day | <0.03 | 0.03–0.05 | >0.05 | |
| Number of cases, n | 102 | 122 | 94 | |
| Basic RR (95% CI) | 1.00 | 1.12 (0.86–1.45) | 0.81 (0.61–1.07) | 0.13 |
| Multivariate RR (95% CI) | 1.00 | 1.11 (0.85–1.44) | 0.79 (0.59–1.04) | 0.10 |
| DHA (C22:6), g/day | <0.07 | 0.07–0.13 | >0.13 | |
| Number of cases, n | 100 | 119 | 106 | |
| Basic RR (95% CI) | 1.00 | 1.18 (0.90–1.54) | 0.97 (0.73–1.28) | 0.78 |
| Multivariate RR (95% CI) | 1.00 | 1.17 (0.90–1.53) | 0.96 (0.72–1.26) | 0.73 |
| Sum of omega-6, g/dayf | <7.17 | 7.17–8.91 | >8.91 | |
| Number of cases, n | 118 | 92 | 115 | |
| Basic RR (95% CI) | 1.00 | 0.74 (0.56–0.97)* | 0.88 (0.68–1.15) | 0.37 |
| Multivariate RR (95% CI) | 1.00 | 0.74 (0.56–0.97)* | 0.86 (0.66–1.12) | 0.28 |
| Linoleic acid (C18:2), g/day | <7.06 | 7.06–8.80 | >8.80 | |
| Number of cases, n | 117 | 93 | 115 | |
| Basic RR (95% CI) | 1.00 | 0.76 (0.58–1.00) | 0.89 (0.69–1.16) | 0.41 |
| Multivariate RR (95% CI) | 1.00 | 0.75 (0.57–0.99)* | 0.86 (0.67–1.14) | 0.32 |
| AA (C20:4), g/day | <0.07 | 0.07–0.10 | >0.10 | |
| Number of cases, n | 113 | 122 | 90 | |
| Basic RR (95% CI) | 1.00 | 1.10 (0.85–1.43) | 0.90 (0.60–1.05) | 0.12 |
| Multivariate RR (95% CI) | 1.00 | 1.08 (0.84–1.40) | 0.78 (0.59–1.03) | 0.09 |
| Omega-3/omega-6 ratio | <0.11 | 0.11–0.14 | >0.14 | |
| Number of cases, n | 115 | 98 | 112 | |
| Basic RR (95% CI) | 1.00 | 0.88 (0.67–1.16) | 0.94 (0.72–1.22) | 0.65 |
| Multivariate RR (95% CI) | 1.00 | 0.91 (0.69–1.19) | 0.94 (0.72–1.22) | 0.65 |
a
All P values from 2-sided tests.
b
Sum of omega-3: α-linolenic acid, eicosapentaenoic acid (EPA), docosapentaeoic acid (DPA), docosahexaenoic acid (DHA).
c
RRbasic adjusted for age and sex.
d
RRmv.adj adjusted for age, sex, freckling on back, elastosis of neck, treatment allocation.
e
Sum of long-chain omega-3: EPA, DPA, DHA.
f
Sum of omega-6: linoleic acid, arachidonic acid (AA).
*
P < 0.05.