Body size in early life and risk of lymphoid malignancies and histological subtypes in adulthood

Abstract

Risk of adult lymphoid malignancy is associated with recent adiposity. Some have reported apparent associations with adiposity in childhood or early adulthood, but whether these associations are independent of recent adiposity is unknown. Birth weight, body size at age 10 years, clothes size at age 20 years, and recent body mass index (BMI) were recorded in 745,273 UK women, mean age 60.1 (SD 4.9) at baseline, without prior cancer. They were followed for 11 years, during which time 5,765 lymphoid malignancies occurred. Using Cox regression, a higher risk of lymphoid malignancy was strongly associated with higher recent BMI (RR=1.33, 95%CI 1.17-1.51, for BMI 35+ vs <22.5 kg/m(2)), and this association remained essentially unchanged after adjustment for birth weight and body size at 10. Higher lymphoid malignancy risk was also associated with large size at birth, at age 10, and at age 20 years, but after adjustment for recent BMI, the significance of the associations with large size at birth and at age 10 years was sufficiently reduced that residual confounding by adult BMI could not be excluded; a weak association with large size at 20 years remained (adjusted RR =1.17, 95%CI 1.10-1.24 for large size at age 20 vs. medium or small size). We found no strong evidence of histological specificity in any of these associations. In conclusion, our findings suggest a possible role of adiposity throughout adulthood in the risk of lymphoid malignancy, but the independent contribution of body size at birth and during childhood appears to be small.

Keywords: body mass index; childhood obesity; lymphoid malignancies; lymphoma; myeloma; obesity.

Figure 1

Relative risk of lymphoid malignancy by early body size variables within categories of recent body mass index (BMI). Body size variables were reported at about age 60 years, on average 7 years before lymphoid malignancy diagnosis. P values are for differences between pairs.