Central obesity predicts non-Hodgkin's lymphoma mortality and overall obesity predicts leukemia mortality in adult Taiwanese.

OBJECTIVE

Obesity may increase the risk of neoplasia, including that of the lymphohematopoietic system. In a large Taiwanese cohort, we have evaluated whether body fat and its distribution is associated with non-Hodgkin's lymphoma (NHL) and leukemia mortalities.

METHODS

During 1997-2007 in Taiwan, 383,956 subjects aged 19-98 years without any cancer history were obtained through a health screening center and followed up for a median of 7.2 years. Unit records were linked to the national death registry; ICD-9 codes were used to identify 143 NHL and 73 leukemia deaths. Objectively, height, weight, and waist circumference data were measured to calculate body mass index (BMI) and central obesity status. Based on World Health Organization criteria modified for Asia and Taiwan, BMI was classified to <18.5, 18.5-23.9, 24-26.9, and ≥ 27 kg/m(2). Waist circumference ≥ 90 cm in men and ≥ 80 cm in women was defined as central obesity. Cox proportional hazard regression models were adjusted for possible confounders including gender, age, education, smoking status, alcohol consumption, physical activity, and clinic location.

RESULTS

BMI was not associated with NHL deaths, although the trend was significant, but central obesity with adjustment was (hazard ratio [HR] = 1.87, 95% confidence interval [CI] = 1.27-2.75) compared with non-centrally obese subjects. BMI, but not central obesity, was associated with leukemia mortality (HR = 1.93, 95% CI = 1.00-3.75).

CONCLUSIONS

An increased risk for NHL with increased abdominal fatness and more so with lower BMI is apparent in Taiwanese; this may indicate that metabolically localized and proinflammatory fat is important. For leukemia, where most is myeloid leukemia, increased general fatness is evidently a risk with Taiwanese ethnicity.