Exploratory Factor Analysis of Squamous Cell Carcinoma of the Esophagus in Uruguay

Abstract

In the period 1996–2004, a hospital-based, case-control study on diet and risk of squamous cell carcinoma of the esophagus was conducted in Montevideo, Uruguay. The study included 234 cases and 468 controls, frequency matched on age, sex, and residence. Factor analysis (principal components) was used to identify the major food patterns associated with esophageal cancer. The analysis of food groups led to the identification of four patterns, arbitrarily labeled as traditional, healthy, high-fat, and drinker. The traditional pattern was not associated with risk of esophageal carcinoma, whereas the healthy pattern displayed a strong inverse association with this malignancy [odds ratio (OR) 0.29, 95% confidence interval (CI) 0.17–0.48, P value for trend < 0.0001]. Unexpectedly, the high-fat foods diet was also marginally protective (OR 0.60, 95% CI 0.36–1.01, P value for trend = 0.07). On the other hand, the drinker pattern displayed a twofold increase in risk of esophageal carcinoma (OR 2.03, 95% CI 1.17–3.51, P value for trend = 0.01). The present study suggests that factor analysis might contribute to the elucidation of the contribution of diet on human cancer. Because diet represents a complex set of highly correlated exposures, dietary patterns could be more explicative of the etiology of squamous cell carcinoma of the esophagus than the traditional reductionist approach.

ACKNOWLEDGMENT

This study was supported by a grant from International Agency for Research on Cancer, Lyon, France.

Notes

^a Loading higher than 0.49 are typed in boldface.

^a Abbreviation is as follows: BMI, body mass index. Correlations higher than 0.09 are usually significant at alpha = 0.05.

^b Pearson correlation.

^c Spearman correlation.

^a Abbreviations are as follows: OR, odds ratio; CI, confidence interval. Age and sex adjusted.

^b Adjusted for age, sex, residence, urban/rural status, birthplace, education, family history of esophageal cancer among first-degree relatives, body mass index, smoking status, years since quit, cigarettes per day, maté temperature, and total energy intake.

^a Abbreviations are as follows: OR, odds ratio; CI, confidence interval. Adjusted for age, residence, urban/rural status, birthplace, education, family history of esophageal cancer among first-degree relatives, body mass index, smoking status, years since quit, cigarettes per day among current smokers, maté temperature, and total energy intake.

^a Abbreviations are as follows: OR, odds ratio; CI, confidence interval. Adjusted for age, sex residence, urban/rural status, birthplace, education, family history of esophageal cancer among first-degree relatives, body mass index, years of smoking, maté temperature, and total energy intake.