Tuberculosis continues to be a significant public health concern in China, particularly among the elderly population. This study aimed to assess the risk factors of tuberculosis among elderly individuals in China through a cohort study, focusing on this high-risk population. The population-based census was strategically designed to cover diverse regions and demographics across the city. The survey captured demographic and lifestyle information, as well as a clinical examination. Participants were prospectively followed up over a specified duration to monitor the incidence of tuberculosis cases. After a follow-up period of more than 7 years, 246 individuals developed tuberculosis, resulting in an incidence rate of 92.21 per 100,000 person-years (95 % CI 81.2-104.3). In multivariate analysis, the following factors were found to have significant associations with active tuberculosis. Increasing age correlated with a higher risk of active tuberculosis (AHR = 1.03 per 1-year increase in age, 95%CI: 1.01, 1.04, P < 0.001). Males continued to have a higher risk compared to females (HR = 2.73, 95%CI: 2.08, 3.58, P < 0.001). Individuals with a normal Body Mass Index (BMI) faced nearly three times higher risk compared to their obese counterparts (HR = 2.87, 95 % CI: 1.51, 5.46, P = 0.001). Conversely, those with an underweight BMI had a ten-fold higher risk compared to the obese group (HR = 9.89, 95 % CI: 4.92, 19.85, P < 0.001). Elderly individuals who quit smoking had a 1.35-fold increased risk compared to non-smokers (HR = 1.35, 95%CI: 1.12, 1.64, P < 0.001). Tuberculosis incidence among the elderly population in China remained alarmingly high. This finding emphasizes the urgent need for implementing proactive case detection measures specifically tailored to address the specific needs of this vulnerable demographic, particularly in individuals who are male, have a history of former or current smoking, and have a low BMI. Moreover, we must not underestimate the influence of former smoking on tuberculosis risk.

Flatfoot is a common foot deformity, and the collapse of the arch structure affects the foot cushioning during walking. A growing number of scholars have found that the analysis of the impact force should be combined with both the magnitude and the frequency of the impact force. Therefore, the aim of this study is to investigate the plantar impact characteristics of flatfoot patients and normal foot people at different load-bearing buffer stage from the time and frequency domains. Sixteen males with flatfoot and sixteen males with normal foot were recruited to walk on the plantar pressure test system at the same step speed, and the vertical ground reaction force data were collected from the heel contact stage and the arch support stage. The differences in the frequency domain of the ground reaction force between the flatfoot and the normal foot in the two stages were analyzed according to the basic mechanical characteristics and the continuous wavelet transform. Independent sample t-test was used to compare the baseline data of subjects, and the differences in foot impact force characteristics at different stages of foot type and weight-bearing cushion phase were compared by two-factor repeated measures Analysis of Variance. 1) In terms of basic mechanical characteristics, In both groups for flatfoot patients and normal foot people, the peak ground reaction force was higher in the arch support stage compared to the heel contact stage (P_flatfoot<0.001, P_{normal foot}<0.001), and the load rate of force change was smaller in this stage (P_flatfoot<0.001, P_{normal foot} 0.05), in the arch support stage, the force change load rate of patients with flatfoot was lower than that of normal foot people (p = 0.021). 2) The results of time and frequency domain characteristics showed that during the heel contact and the arch support stage, no significant differences in the maximum signal power as well as the corresponding time and the frequency of the main impact force between the normal foot and the flatfoot were found. In both flatfoot and normal foot types, compared with the foot heel contact stage, the maximum signal power in the arch support stage was higher (P_flatfoot < 0.001, P_{normal foot}<0.001), and the corresponding impact frequency was smaller (P_flatfoot = 0.002, P_{normal foot} = 0.004). Once the step speed was controlled, the flatfoot patients only showed a smaller impact force load rate in the arch support stage, which may be related to their lower arch rigidity. The characteristics of the impact force in different stages of walking support period were different in time and frequency domain, suggesting that there may be differences in the function of various parts of the foot.

Primary Mycobacterium tuberculosis transmission is an important driver of the global epidemic of resistance to tuberculosis drugs. A few studies have compared tuberculosis infection in contacts of index cases with different drug-resistant profiles, suggesting that contacts of multidrug-resistant (MDR) tuberculosis cases are at higher risk. Repeated tuberculosis exposure in contacts of MDR tuberculosis patients through recurrent tuberculosis may modify this relationship. We compared tuberculosis infection in household contacts of MDR and drug-susceptible (DS) tuberculosis patients from six cities in southeastern China and investigated whether repeated tuberculosis exposure was a mediating factor. Tuberculosis infection was defined as a tuberculin skin test induration ≥ 10 mm. In all, 111 (28.0%) of 397 household contacts of MDR tuberculosis patients and 165 (24.7%) of 667 contacts of DS tuberculosis index cases were infected with tuberculosis. In a multivariate model not including the previous tuberculosis exposure, contacts of MDR tuberculosis patients had a higher likelihood of tuberculosis infection (adjusted odds ratio [AOR] = 1.37; 95% confidence interval [CI] = 1.01–1.84; P = 0.041). In a separate multivariate model adjusted for the previous tuberculosis exposure, the odds ratio of tuberculosis infection flipped and contacts of MDR cases were now at lower risk for tuberculosis infection (AOR = 0.55; 95% CI = 0.38–0.81; P = 0.003). These findings suggest prior tuberculosis exposure in contacts strongly mediates the relationship between tuberculosis infection and the index drug resistance profile. Prior studies showing lower risk of developing tuberculosis among contacts of MDR tuberculosis patients may be partially explained by a lower rate of tuberculosis infection at baseline.

The low positive predictive value of tuberculin skin tests and interferon-γ release assays often results in unnecessary prophylaxis. This study aimed to identify antigen-specific biomarkers with high accuracy for predicting progression to active tuberculosis (ATB). QuantiFERON supernatants from a school tuberculosis outbreak cohort were analyzed, tracking students over two years to identify ATB cases. We assessed 67 cytokines using the Luminex Multiplex Array kit and applied LASSO and multivariate logistic regression to select predictors. A nomogram was developed from the coefficients of top predictors. Model performance was evaluated by AUC, C-index, and AIC. The levels of FGFbasic, GM-CSF, MPIF-1/CCL23, as well as the combinations of ratios of FGFbasic/GM-CSF and FGFbasic/MPIF-1/CCL23 were significantly associated with the risk of ATB. AUC values for the prediction models based on individual cytokines ranged from 0.607 to 0.713, notably lower than those of the fixed models based on the logistic regression (0.932) and LASSO regression (0.939). The LASSO regression model exhibited the best predictive performance, with a higher sensitivity (0.858 vs. 0.818) and specificity (0.949 vs.0.923), lower AIC (36.323 vs. 38.232), and equivalent C-index (0.939) compared to the traditional logistic regression model. The biomarkers identified in this study offer valuable insights for developing a more precise tool to identify individuals at high risk for rapid progression to ATB disease, enabling targeted interventions. The combination of multiple immune indicators shows significant promise in improving diagnostic accuracy.

Background: Tuberculosis (TB) is a leading cause of death among people living with HIV (PLHIV). While body mass index (BMI) affects TB risk, its association with latent tuberculosis infection (LTBI) in PLHIV is unclear. High-transmission settings, such as prisons, may further increase LTBI risk, yet this relationship has not been studied across both prison and community populations of PLHIV. Methods: We conducted a dual cross-sectional study of PLHIV in Jiangsu Province, China, recruiting participants from a prison hospital in 2021 and community healthcare facilities from July to November 2023. BMI was calculated from measured height and weight. LTBI was identified by a positive ESAT6-CFP10 (EC) skin test or the QuantiFERON-TB Gold In-Tube (QFT-GIT) assay. Logistic regression and generalized additive models (GAMs) assessed the association between BMI and LTBI, adjusting for demographic, clinical, and behavioral confounders. Results: A total of 1799 PLHIV were included in the analysis, of whom 343 (19.07%) were recruited from prison settings and 1456 (80.93%) from community-based screening. The overall prevalence of LTBI was 13.79% (n = 248). Obesity (BMI ≥ 28 kg/m²) was linked to a significantly lower risk of LTBI (adjusted OR = 0.47, 95% CI: 0.23–0.95, p = 0.036), particularly when identified by EC testing (adjusted OR = 0.13, 95% CI: 0.03–0.54, p = 0.005). The BMI–LTBI association followed a nonlinear “U-shaped” pattern, with the lowest prevalence in individuals who were obese. Among those with CD4+ T cell counts < 500 cells/μL, the inverse association between obesity and LTBI was even more marked (adjusted OR = 0.20, 95% CI: 0.05–0.83, p = 0.027). Conclusion: In summary, obesity is significantly associated with a lower risk of LTBI among PLHIV, with an approximate 54% risk reduction. This inverse relationship was most pronounced when using the EC skin test.