Association between DNA repair capacity and body mass index in women

Objective

Examine whether DNA repair capacity (DRC) levels are associated with body mass index (BMI) in adult women.

Design and participants

A nested study composed of 539 women without breast cancer (BC) from a case-control BC study in addition to 104 that were recruited later for a total of 643.

Measurements

DRC levels were measured in lymphocytes using a host-cell reactivation assay with a luciferase reporter gene damaged by UVC. This assay measures the efficiency of nucleotide excision repair (NER). Log-binomial regression model was used. The prevalence ratio (PR) was used to evaluate the magnitude of the association between the BMI and DRC levels. An assessment of interaction terms was performed with the likelihood ratio test. The confounding effect was assessed by comparing the point estimates of the crude and adjusted PR.

Results

The 75th percentiles of DRC levels of the women with a BMI between 18 and 25 and > 25 showed statistically significant differences. The prevalence of a DRC ≤ 5 % among women with BMI > 25 is 1.24 (95 % CI: 1.03, 1.48) times the prevalence of having a DRC ≤ 5 % among the women with BMI ≤ 25 after adjustments for different covariates. This excess was statistically significant (p < 0.05). Women with a family history of cancer had an estimated PR of 1.25 (95 % CI, 0.87–1.39; P ≥ 0.05); and women with no family history of cancer, the estimated PR was 1.6 (95 % CI, 1.14–2.22; p ≤ 0.05).

Conclusions

Women with BMI > 25 tend to have lower DRC levels. When having a family history of cancer, the PR of low DRC levels in overweight/obese individuals was not statistically significant. However, the PR of low levels of DRC in overweight/obese individuals with no family history of cancer was statistically significant.