Abstract
Background: Obesity has been associated with risk of non-Hodgkin lymphoma (NHL) in several recent studies. However, the effect of weight gain during adulthood, a potentially modifiable risk factor, on the incidence of NHL is not clear. We therefore examined the association of weight gain since age 18 years with the risk of NHL among older women.
Methods: We examined this association in the Iowa Women’s Health Study, a prospective study of 37,762 Iowa women aged 55 to 69 years at enrollment in 1986. Lifestyle and other risk factors, including weight at age 18 and at enrollment, were self-reported on a mailed questionnaire. We defined stable weight as no increase in weight or up to a 10% weight loss from age 18 to enrollment, while percent weight gain was divided into tertiles based on the distribution observed in the cohort. NHL incidence through 18 years of follow-up was ascertained by linkage with the Iowa SEER Cancer Registry. Cox proportional hazards models were used to estimate relative risks (RRs) and 95% confidence intervals (CIs) of percent weight gain with NHL incidence, adjusting for age (Age-adjusted model) and age, marital status, farm residence, transfusion history, diabetes, use of hormone replacement therapy, alcohol use, smoking, and intake of red meat and fruits (Multivariate model).
Results: The mean age of the women in the cohort in 1986 was 62.1 years. During 593,474 person-years of follow-up, 379 incident cases of NHL were observed. The mean age at diagnosis was 72.6 years (range 58–87 years). The main results are reported in the table. Similar results were found for absolute weight gain. Stratification of these results on body mass index at age 18 (using a cutpoint of 21 kg/m2) showed similar results, with the exception of >10% weight loss for women with a BMI of <21 at age 18 where we could not estimate a RR (no cases observed).
Conclusions: Weight gain or large weight loss (>10% of body weight) during adulthood were both associated with increased risk of NHL, although the RRs for percent weight gain were not statistically significant and there was no dose-response. This study suggests another potential benefit of avoiding adult weight gain, although further studies are needed to confirm these novel findings.
Association of percent weight change during adulthood (age 18 to age 55–69 years) and risk of NHL
| % Weight Change . | NHL Cases . | Person-years . | Age-Adjusted RR(95% CI) . | Multivariate RR (95% CI) . |
|---|---|---|---|---|
| >10% weight loss | 15 | 17053 | 2.06 (1.05–4.02) | 2.02 (1.03–3.95) |
| Stable | 20 | 45973 | 1 (reference) | 1 (reference) |
| 0–18.2% gain | 115 | 175883 | 1.50 (0.94–2.42) | 1.50 (0.93–2.41) |
| 18.3–34.8% gain | 119 | 176258 | 1.54 (0.96–2.47) | 1.53 (0.95–2.47) |
| >34.8% gain | 110 | 178308 | 1.40 (0.87–2.25) | 1.32 (0.82–2.14). |
| % Weight Change . | NHL Cases . | Person-years . | Age-Adjusted RR(95% CI) . | Multivariate RR (95% CI) . |
|---|---|---|---|---|
| >10% weight loss | 15 | 17053 | 2.06 (1.05–4.02) | 2.02 (1.03–3.95) |
| Stable | 20 | 45973 | 1 (reference) | 1 (reference) |
| 0–18.2% gain | 115 | 175883 | 1.50 (0.94–2.42) | 1.50 (0.93–2.41) |
| 18.3–34.8% gain | 119 | 176258 | 1.54 (0.96–2.47) | 1.53 (0.95–2.47) |
| >34.8% gain | 110 | 178308 | 1.40 (0.87–2.25) | 1.32 (0.82–2.14). |
Disclosure: No relevant conflicts of interest to declare.
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