Abstract

OBJECTIVES:

• To review all prospective studies which published information about eggs in relationship with total cancer risk, and total cancer mortality.
• To define the amount of consumption found to be related with possible effects on total cancer.
• To define possible effect modification by confounders.

DATA SOURCE: The Pubmed database was searched (No start date - May 25th, 2010) for relevant articles using the keywords "dietary cholesterol, dietary fat, egg, or eggs" combined with "prospective, cohort, follow-up, or longitudinal". The exact search term is described Here.
Prospective studies published in the English language were included. Reference lists were searched for additional articles.
RESULTS: 5 articles were found which provided information about 5 different cohorts. Of these, 0 articles were excluded.

• Total disease risk.
  Data about 2 cohorts was found including 5,694 cases. No evidence was found for an association.
• Mortality risk.
  Data about 4 cohorts was found including 8,110 cases. No evidence was found for an association.

CONCLUSION: Results were restricted to findings from only 5 cohorts. Few associations were found. In addition, in only 2 cohorts were results presented about egg consumption as a categorized variable with at least 3 different, and clearly defined units of consumption. Therefore, it is impossible to examine the possibility of an effect from intermediate levels of consumption. Currently, no evidence was found for an association between any level of egg consumption and total cancer risk or total cancer mortality.
LIMITATIONS: Two out of five cohorts were of (very) small size, further limiting the level of evidence. And no data was available about possible effect modification by confounders. Further prospective data is clearly needed to prove any possible effect between egg consumption and major chronic disease.

Eggs and total cancer risk.

2 articles, providing information about 2 different cohorts were found, including 5,694 cases.
Results: A significantly increased risk was found in one European cohort, including 851 cases (Benetou V). But no association was found in the other cohort, including 4,843 postmenopausal women (Kelemen LE).
Effect modification: No data was found.

Conclusion: Results were limited to data from 2 cohorts. A significantly increased risk was found in the cohort with the smallest amount of cases. No evidence was found for an association between egg consumption and total cancer risk.

Eggs and total cancer mortality.

4 articles, providing information about 4 different cohorts were found, including 8,110 cases.

Results: Increased risks were found among both men and women in one cohort (Nakamura Y), including 356 cases. Among men the RR, but not the trend was significantly increased. While among women the trend was nonsignificantly increased, but the RR was not. No associations were found in the remaining 3 cohorts.
Effect modification: No data was found.

Conclusion: Any effects of high vs low consumption were restricted to findings from one cohort of small size. No evidence was found for an association between egg consumption and total cancer mortality.