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Number of full sisters with colorectal cancer


FSNCLRCAN is a two-digit count variable.

00: Not in Universe
03: Top code of 3 or more
97: Unknown-Refused
98: Unknown-Not Ascertained
99: Unknown-Don't Know


For sample adults with at least one full sister who ever had colorectal cancer (FSCLRCAN), FSNCLRCAN reports the number of full sisters who had ever been told they had colorectal cancer. Only persons with at least one full sister (FSNUM) who ever had cancer of any kind (FSNHCAN) were asked follow-up questions about what kind(s) of cancer their full sister(s) had, and about the number of full sisters they had with the specified type(s) of cancer (such as colorectal cancer).
In 2015, due to low frequencies among family members, colon and rectal cancers were removed from the NHIS public use file to maintain respondent confidentiality. Therefore, from 2015 NHIS does not provide colon and rectal cancer variables separately, and instead a series of "colorectal cancer" variables was created. Researchers may choose to recode the colon and rectal cancers variables FSNCLCAN and FSNRTCAN in 2000, 2005 and 2010 to mimic the "colorectal cancer" variables in 2015.

FSNCLRCAN is one of a series of related variables in the "Family History" section of the 2000 and later Cancer Modules. In all years, this section begins with the general comment:

We would like to ask you a few questions about your family history of cancer.

According to the 2000 and 2005 Field Representative's Manuals, the purpose of this and other family cancer history questions is to "determine the prevalence of cancer in families in the population" to "allow a greater understanding of how data obtained from genetics clinics can be applied to the general population." The 2010 and later Manuals provide a similar rationale, stating that the collection of these data "will allow analysts a greater understanding of how family history relates to cancer.
The Manuals for all years define "full siblings" as people who have "the same biological father and mother." Thus, a respondent's full sister is a sister who has the same biological father and mother as the respondent (i.e., not half-sisters, stepsisters, adopted sisters, foster sisters, or sisters-in-law).


There are no comparability issues.


  • 2015: Sample adults aged 18 and older whose biological sister(s) was ever diagnosed with colorectal cancer.


  • 2015