Background: Muscle quality is associated with fatty degeneration or infiltration of the muscle, which may be associated with decreased muscle function and increased disability. Objective: The aim of this study is to evaluate the feasibility of automated quantitative measurements of the skeletal muscle on computed tomography (CT) images to assess normal-attenuation muscle and myosteatosis. Methods: We developed a web-based toolkit to generate a muscle quality map by categorizing muscle components. First, automatic segmentation of the total abdominal muscle area (TAMA), visceral fat area, and subcutaneous fat area was performed using a predeveloped deep learning model on a single axial CT image at the L3 vertebral level. Second, the Hounsfield unit of each pixel in the TAMA was measured and categorized into 3 components: normal-attenuation muscle area (NAMA), low-attenuation muscle area (LAMA), and inter/intramuscular adipose tissue (IMAT) area. The myosteatosis area was derived by adding the LAMA and IMAT area. We tested the feasibility of the toolkit using randomly selected healthy participants, comprising 6 different age groups (20 to 79 years). With stratification by sex, these indices were compared between age groups using 1-way analysis of variance (ANOVA). Correlations between the myosteatosis area or muscle densities and fat areas were analyzed using Pearson correlation coefficient r. Results: A total of 240 healthy participants (135 men and 105 women) with 40 participants per age group were included in the study. In the 1-way ANOVA, the NAMA, LAMA, and IMAT were significantly different between the age groups in both male and female participants (P≤.004), whereas the TAMA showed a significant difference only in male participants (male, P<.001; female, P=.88). The myosteatosis area had a strong negative correlation with muscle densities (r=–0.833 to –0.894), a moderate positive correlation with visceral fat areas (r=0.607 to 0.669), and a weak positive correlation with the subcutaneous fat areas (r=0.305 to 0.441). Conclusions: The automated web-based toolkit is feasible and enables quantitative CT assessment of myosteatosis, which can be a potential quantitative biomarker for evaluating structural and functional changes brought on by aging in the skeletal muscle.

Objectives Limited evidence suggests the association between severity of acute occupational pesticide poisoning and depressive symptoms in farmers. The aim of this study was to investigate the association between occupational pesticide exposure and depressive symptoms among male farmers in South Korea. Methods A nationwide sampling survey of male farmers was conducted in South Korea. A total of 1958 male farmers were interviewed in 2011. Severity of occupational pesticide poisoning was evaluated according to symptoms, types of treatment and number of pesticide poisonings per individual. Depressive symptoms were assessed using the Geriatric Depression Scale. A survey logistic regression model was used to estimate the multivariate OR and 95% CIs. Results Among total farmers, 10.4% (n=197) reported depressive symptoms. After controlling for potential confounders, occupational pesticide poisoning in the previous year was positively associated with the risk of depressive symptoms (OR=1.61; 95% CI 1.10 to 2.34). Cases of more severe pesticide poisoning, such as moderate- or severe-symptom cases (OR=2.81; 95% CI 1.71 to 4.63), outpatient or hospitalisation cases (OR=2.52; 95% CI 1.15 to 5.53), and multiple poisoning cases (OR=1.82; 95% CI 1.19 to 2.76) showed higher risks of depressive symptoms than did milder cases. Among the pesticides causing the poisonings, paraquat dichloride was found to be a significant predictor of depressive symptoms. No significant association was found with cumulative lifetime pesticide application and depressive symptoms. Conclusions Our findings suggest that the risk of depression appears to be related to the severity of symptoms of poisoning, type of care received and the number of previous episodes of acute poisonings.

Kim DW, et al. Korean J Radiol. 2021 Apr;22(4):624-633. https://doi.org/10.3348/kjr.2020.0914

This study extended and updated a meta-analysis of the association between exposure to dichlorodiphenyltrichloroethane (DDT) and the risk of breast cancer. We reviewed the published literature on exposure to DDE and breast cancer risk to update a meta-analysis from 2004. The total of 35 studies included 16 hospital-based case-control studies, 11 population-based case-control studies, and 10 nested case-control studies identified through keyword searches in the PubMed and EMBASE databases. The summary odds ratio (OR) for the identified studies was 1.03 (95% confidence interval 0.95-1.12) and the overall heterogeneity in the OR was observed (I (2) = 40.9; p = 0.006). Subgroup meta-analyses indicated no significant association between exposure to DDE and breast cancer risk by the type of design, study years, biological specimen, and geographical region of the study, except from population-based case-control studies with estimated DDE levels in serum published in 1990s. Existing studies do not support the view that DDE increases the risk of breast cancer in humans. However, further studies incorporating more detailed information on DDT exposure and other potential risk factors for breast cancer are needed.

Kim DW, et al. Korean J Radiol. 2022 Nov;23(11):1055-1066. https://doi.org/10.3348/kjr.2022.0277