Lifecourse influences on osteoarthritis of the knees, hips and hands as defined by musculoskeletal ultrasound

Abstract

Aims: There has been very little lifecourse research looking at the risk of osteoarthritis (OA). A lifecourse analysis of risk factors for knee, hip and hand OA (defined using features on ultrasound) acting at different stages of life, including early life factors, was performed among members of the Newcastle Thousand Families birth cohort. Methods: Potential risk factors for OA (including birth weight, breast feeding data and socioeconomic status) have been collected prospectively in this birth cohort of subjects aged 63 (born in May-June 1947) and an a priori conceptual framework was developed. Subjects had both knees, hips and the dominant hand scanned with ultrasound. These data were analysed in relation to a range of factors from across the lifecourse using logistic and linear regression models.

Results: Among 316 participants, duration of exclusive breast feeding showed a significant inverse association with knee osteophytes while BMI and total hip bone mineral density at age 50 increased the risk of knee osteophytes. The univariate effect of social class at birth on knee osteophytes was found to be mediated by its subsequent effect on breast feeding and total hip bone mineral density. The multivariate model for hip OA had three risk factors; BMI, physical activity and pack years of smoking at age 50. Smoking at age 50 and increased infections in childhood appeared to confer protection from hand OA.

Conclusions: This is the first study to perform a lifecourse analysis of OA risk using prospectively collected data. The majority of the risk of OA at the three joint sites seemed to occur through factors acting in adulthood. However, breast feeding protected subjects from knee OA while infections in childhood decreased hand OA risk. These results suggest that modification of OA risk factors acting in adulthood would probably be more beneficial than intervening in early life.