Discovering the causes of cancer and the means of prevention
Nurses Health Study I
The Nurses Health Study (NHS) questionnaire had the following questions involving chicken skin.
When you eat chicken, how often is it cooked with the skin on?
- always
- most of the time
- sometimes
- never
How often do you eat the skin?
- always
- most of the time
- sometimes
- never
The same calculations were applied to NHS as the Health Professionals Follow-up Study (HPFS). In order to account for the four answers, the following percentages were applied:
- Always (100%)
- Most of the time (75%)
- Sometimes (50%)
- Never (0%)
The following table illustrates the number of different combinations possible.
| Percentage used in calculation | Cook with skin | Eat skin |
|---|---|---|
| 100% cook w/skin and eat w/skin | Always | Always |
| 75% cook w/skin and eat w/skin 25% cook w/skin and eat w/o skin | Always | Most |
| 50% cook w/skin and eat w/skin 50% cook w/skin and eat w/o skin | Always | Sometimes |
| 100% cook w/skin and eat w/o skin | Always | Never |
| 25% cooked w/o skin 75% cooked w/skin and eat w/skin | Most | Always |
| 25% cooked w/o skin, 56% cooked w/ skin and eat w/skin 19% cooked with skin and eat w/o skin | Most | Most |
| 25% cooked w/o skin 37.5% cooked w/skin and eat w/skin 37.5% cooked with skin and eat w/o skin | Most | Sometimes |
| 25% cooked w/o skin 75% cooked w/skin and eat w/o skin | Most | Never |
| 50% cooked w/o skin 50% cooked w/skin and eat w/skin | Sometimes | Always |
| 50% cooked w/o skin 37.5% cooked w/skin and eat w/skin 12.5% cooked with skin and eat w/o skin | Sometimes | Most |
| 50% cooked w/o skin 25% cooked w/skin and eat w/skin 25% cooked with skin and eat w/o skin | Sometimes | Sometimes |
| 50% cooked w/o skin 50% cooked with skin and eat w/o skin | Sometimes | Never |
| 100% cooked w/o skin | Never | Never |
A complete listing of the values is available.
For more information:
Kana Wu, MD, PhD
Harvard School of Public Health
Department of Nutrition
665 Huntington Avenue
Boston, MA 02115
Tel. 617-432-1842
Fax. 617-432-2435
e-mail:kana.wu@channing.harvard.edu