Approved research

Long term dairy consumption and colorectal cancer risk in adulthood

Lay summary

This study aims to elucidate the relationship between long term dairy consumption and colorectal cancer risk in adulthood. Colorectal cancer (CRC) is the third most commonly diagnosed cancer in the world. The majority of research investigating how dairy intake is associated with CRC risk asked their participants to recall their diets over the past year; the decreased cancer incidence among the high dairy intake group may be due to the short-term effects of the anti-inflammatory properties of the nutrients in milk. But the long induction period of CRC suggests that early-life diet may affect CRC pathogenesis in adulthood. Studies assessing how childhood dairy intake affects CRC risk later in life reported significant increases in CRC incidence among the highest consumers of dairy products; however, such studies did not control for confounding dietary factors and did not stratify by sex, by tumor sublocation, or by type of dairy product, prompting the need for improved methods of analysis. The results of this study will increase knowledge regarding the effects of early-life dairy consumption on carcinogenesis in adulthood and will further understanding on the role of Western diet regarding CRC. We will estimate cox proportional hazards models between CRC incidence of those who reported to have never consumed dairy vs CRC incidence of the highest consumers of dairy while controlling for possible confounding factors and stratifying by sex, by calcium intake, by lactose intolerance, and by type of dairy consumption. This project is important in the field of public health as it will help clear up the discrepancy between how short-term and long-term dairy consumption relate to CRC risk. The societal implications of studies on this topic are also paramount to our approach to childhood diet, health, and lifestyle: should this study demonstrate that long term dairy consumption decreases CRC risk, milk may play an even larger role in early-life diet that it currently does. But if long term dairy consumption is shown to increase CRC incidence, the actions and promotions of milk by the dairy industry will be shown to have compromised the health of generations of Americans; such a result will change perception of corporate interests in the health of their customers and of the western diet overall.