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Understanding variation in disease risk: the elusive concept of frailty.

Aalen OO, Valberg M, Grotmol T, Tretli S - Int J Epidemiol (2014)

Bottom Line: Heterogeneity often manifests itself as clustering of cases in families more than would be expected by chance.We emphasize that apparently moderate familial relative risks can only be explained by strong underlying variation in disease risk between families and individuals.Finally, we highlight the potential impact of frailty variation in the interpretation of standard epidemiological measures such as hazard and incidence rates.

View Article: PubMed Central - PubMed

Affiliation: Oslo Centre for Biostatistics and Epidemiology, Department of Biostatistics, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway and Cancer Registry of Norway, Institute of Population-Based Cancer Research, Oslo, Norway o.o.aalen@medisin.uio.no.

No MeSH data available.


Related in: MedlinePlus

Age-standardized rates (ASR) of colorectal cancer, standardized with respect to the world (W) population, in various regions for 2012. Picture constructed by Globocan10.
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dyu192-F1: Age-standardized rates (ASR) of colorectal cancer, standardized with respect to the world (W) population, in various regions for 2012. Picture constructed by Globocan10.

Mentions: It is often obvious that disease risk is a fluid phenomenon, dependent on environmental and lifestyle risk factors, genes, age and the country of residence, among other things. For example, the risk of being diagnosed with colorectal cancer (CRC) varies widely across different countries; it has increased sharply (in fact more than tripled) in the past few decades in many industrialized countries, and it varies substantially between different countries worldwide. This means that the risk of CRC is not a given quantity, but rather something that varies widely. It would follow that the individual risk of CRC is also a fluid phenomenon; that it varies considerably between individuals even when the outer circumstances are similar. Furthermore, there are large differences in risk across regions (Figure 1).10 Therefore, it seems logical that the risk will not be homogeneous within regions (especially given the arbitrariness of many borders).11 In short, the variation in risk between regions strongly suggests a considerable variation within regions. This kind of variation has been clearly demonstrated for the USA with regard to the dependence on race of CRC incidence.12 However, it is highly likely that there are other variations based on both known and unknown risk factors. Large variations in the susceptibility to CRC have been estimated in Norway,13 and it has been estimated that only 12% of the US population is susceptible to colon cancer.14Figure 1.


Understanding variation in disease risk: the elusive concept of frailty.

Aalen OO, Valberg M, Grotmol T, Tretli S - Int J Epidemiol (2014)

Age-standardized rates (ASR) of colorectal cancer, standardized with respect to the world (W) population, in various regions for 2012. Picture constructed by Globocan10.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4588855&req=5

dyu192-F1: Age-standardized rates (ASR) of colorectal cancer, standardized with respect to the world (W) population, in various regions for 2012. Picture constructed by Globocan10.
Mentions: It is often obvious that disease risk is a fluid phenomenon, dependent on environmental and lifestyle risk factors, genes, age and the country of residence, among other things. For example, the risk of being diagnosed with colorectal cancer (CRC) varies widely across different countries; it has increased sharply (in fact more than tripled) in the past few decades in many industrialized countries, and it varies substantially between different countries worldwide. This means that the risk of CRC is not a given quantity, but rather something that varies widely. It would follow that the individual risk of CRC is also a fluid phenomenon; that it varies considerably between individuals even when the outer circumstances are similar. Furthermore, there are large differences in risk across regions (Figure 1).10 Therefore, it seems logical that the risk will not be homogeneous within regions (especially given the arbitrariness of many borders).11 In short, the variation in risk between regions strongly suggests a considerable variation within regions. This kind of variation has been clearly demonstrated for the USA with regard to the dependence on race of CRC incidence.12 However, it is highly likely that there are other variations based on both known and unknown risk factors. Large variations in the susceptibility to CRC have been estimated in Norway,13 and it has been estimated that only 12% of the US population is susceptible to colon cancer.14Figure 1.

Bottom Line: Heterogeneity often manifests itself as clustering of cases in families more than would be expected by chance.We emphasize that apparently moderate familial relative risks can only be explained by strong underlying variation in disease risk between families and individuals.Finally, we highlight the potential impact of frailty variation in the interpretation of standard epidemiological measures such as hazard and incidence rates.

View Article: PubMed Central - PubMed

Affiliation: Oslo Centre for Biostatistics and Epidemiology, Department of Biostatistics, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway and Cancer Registry of Norway, Institute of Population-Based Cancer Research, Oslo, Norway o.o.aalen@medisin.uio.no.

No MeSH data available.


Related in: MedlinePlus