Lumbar radiculopathy is self-reported based on 2 questions. Participants are first asked if they experienced low back pain that lasted days to months. Those who answer affirmatively are then asked about pain, numbness or tingling, or weakness in the feet or toes.

Participants are asked the following questions:

1. Since your last interview on [last interview date], have you had low back pain that lasted days to months?
2. At a time while you were having low back pain, did you also have pain, numbness or tingling, or weakness in the feet or toes?

Note: This variable is missing if question #1 is missing.

At baseline interview, question #1 reads: Have you ever had low back pain that lasted days to months?