Table III.
Number of non-Hodgkin lymphoma cases and controls and odds ratios according to permanent hair coloring use before 1980, by color, tone, frequency, duration, and total lifetime applications (women only).
| Permanent dye (any) | Permanent, dark colors (black, brown, red) | Permanent, intense tones (black, dark brown, dark blonde) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Hair coloring product use < 1980 | Cases | Controls | ORa (95% CI) | Cases | Controls | ORa (95% CI) | Cases | Controls | ORa (95% CI) | |||
| Frequency (number of applications/year) | ||||||||||||
| 1-4 | 34 | 28 | 1.1 (0.6,2.0) | 20 | 19 | 1.1 (0.6,2.3) | 20 | 9 | 2.2 (0.9,5.3) | |||
| 5-7 | 60 | 39 | 1.5 (0.9,2.5) | 43 | 26 | 1.7 (0.9,3.0) | 22 | 10 | 2.1 (0.9,4.9) | |||
| ≥ 8 | 75 | 56 | 1.2 (0.8,2.0) | 39 | 31 | 1.2 (0.7,2.1) | 19 | 17 | 1.0 (0.5,2.1) | |||
| Duration (years) | ||||||||||||
| 1-4 | 64 | 42 | 1.5 (0.9,2.4) | 42 | 30 | 1.4 (0.8,2.5) | 30 | 20 | 1.5 (0.8,2.9) | |||
| 5-14 | 62 | 47 | 1.2 (0.7,2.0) | 37 | 31 | 1.1 (0.6,2.0) | 14 | 12 | 1.0 (0.4,2.4) | |||
| ≥ 15 | 43 | 34 | 1.2 (0.7,2.1) | 23 | 15 | 1.5 (0.7,3.2) | 17 | 4 | 3.9 (1.2,12.5) | |||
| Cumulative applications | ||||||||||||
| 1-24 | 42 | 56 | 1.3 (0.8,2.2) | 39 | 29 | 1.4 (0.8,2.5) | 27 | 17 | 1.6 (0.8,3.2) | |||
| 25-99 | 36 | 58 | 1.5 (0.9,2.5) | 35 | 22 | 1.5 (0.8,2.8) | 18 | 9 | 1.7 (0.7,4.2) | |||
| ≥ 100 | 45 | 55 | 1.2 (0.7,1.9) | 28 | 25 | 1.1 (0.6,2.1) | 16 | 10 | 1.4 (0.6,3.4) | |||
a
Odds ratio (95% CI), adjusted for age, race, and SEER area, relative to 101 cases and 98 controls who never used hair dye products.