Researchers examined how knee and low back pain/disabilities are correlated in this longitudinal cohort study. They also developed a predictive score that may assist in the identification of people who are likely to develop new knee pain within 5 years. At the first surveillance, a total of 5,932 people aged ≥ 50 years agreed to participate in this study from 2007 to 2010. Then, these respondents of the first survey were sent a second survey in 2015, and 5,576 participants returned the form (94.0% response). According to results from multivariate analyses, significant risk factors for the development of new knee pain in people aged ≥ 50 years who had no, or negligible, knee symptoms were older age, female sex, higher body mass index, lower mental health score, weight increase, and higher low back pain/disability score. The developed predictive score included low back pain/disability score, and indicated that the risk of developing new knee pain within 5 years ranged from 11.0% to 63.2%, depending on the total score.