An analytical method for assessing patterns of familial aggregation in case-control studies

Area of Science:

• Epidemiology
• Biostatistics
• Genetics

Background:

• Family history is crucial for understanding disease patterns.
• Case-control studies collect data on probands and their relatives.
• Quantifying familial aggregation requires robust analytical methods.

Purpose of the Study:

• To present an analytical method for assessing disease aggregation within families.
• To quantify familial aggregation of colorectal cancer using case-control data.
• To investigate the relationship between proband age and familial aggregation of colorectal cancer.

Main Methods:

• Developed an analytical method using case-control study data.
• Modeled relatives' phenotypes based on case-control status and covariates.
• Employed the estimating equations technique to account for correlations between relatives.
• Applied the method to a population-based case-control study of colorectal cancer in Hawaii.

Main Results:

• Colorectal cancer demonstrated significant familial aggregation with an odds ratio of 2.74.
• Familial aggregation was observed in parents (OR=2.38) and siblings (OR=3.09).
• Odds ratios for familial aggregation increased significantly as proband age decreased (OR=7.66 for 40-50 years, OR=12.84 for <40 years).

Conclusions:

• The developed method effectively quantifies familial aggregation in case-control studies.
• Colorectal cancer exhibits strong familial aggregation, particularly in families with younger probands.
• Findings suggest a decrease in familial aggregation of colorectal cancer with increasing proband age.