Prior to 2019, persons with an affirmative response in JNTMO were handed a card showing a figure of the body (front and back) with sixteen joints labeled and numbered (together with the statement, "You may choose more than one."). They were then asked the follow-up question, "Which joints were affected?" Responses to this question were converted into dichotomous variables by the National Center for Health Statistics, with each variable indicating whether the joint was "Mentioned" or "Not mentioned" as being affected. See JNTMOANKLEL for a list of the variables for affected joints.

Persons who answered "Yes" to the question associated with JNTMO were also asked whether their joint symptoms began over 3 months ago (JNT3MOAGO) and whether they had ever talked to a health professional about their joint symptoms (JNTSAWDREV). In some years since 2002, another follow-up question asked respondents to rate how bad their joint pain was during the past 30 days (JNTPAINRATE).

In 1997-2001, sample adults age 18+ were asked whether they had "pain, aching, stiffness or swelling in or around a joint" during the past 12 months (JNTYR). As in 2002 forward, persons who reported having joint problems were asked a follow-up question about which joints were affected (see JNTYRANKLEL for a list of the affected joint variables available in 1997-2001).

Because of the change in the reference period (past 12 months in 1997-2001 versus past 30 days in 2002 forward) and the change in question wording (i.e., back and neck problems were excluded beginning in 2002), the NHIS Survey Descriptions for 2003 forward warn that any comparisons of joint symptom data between the two time periods "should be undertaken with caution."