Objective:To explore the current implementation status and challenges of family doctor contract services (FDCS) from the perspective of contracted residents.Methods:This qualitative study used purposive sampling to select contracted residents from 11 primary healthcare institutions across five cities in China. Semi-structured interviews were conducted from March to December 2024, covering topics such as awareness of contracting, service experience, health needs, service continuity, and policy recommendations. Thematic framework analysis was applied to organize, code, and summarize the data.Results:A total of 25 contracted residents were interviewed (6 men, 19 women; 11 from central urban areas, 14 from suburban or rural towns; 8 with chronic diseases). Three main themes and ten sub-themes emerged: Theme Ⅰ: Pathways to improved service accessibility (optimized chronic disease management, more efficient referrals, and improved health education). Theme Ⅱ: Structural misalignment between supply and demand (limited specialty services despite patient needs, insufficient coverage and public awareness of home-based medical care, imbalanced human resources, and service disruption due to clinician turnover). Theme Ⅲ: Challenges in service awareness and communication mechanisms (information asymmetry and public misperception regarding FDCS, perverse incentives in administrative performance evaluation, and communication barriers in building patient-doctor trust).Conclusions:While FDCS has shown progress in chronic disease management, referral coordination, and health education, structural supply-demand gaps and communication challenges continue to hinder service quality. Improvements in resource allocation and service models are needed to support high-quality development.

Objective:To investigate the relationship between individual and combined exposure to ambient air pollutants and vitamin D, as well as the potential role of ultraviolet radiation (UVR) in mediating the relationships.Methods:This study included 6 967 participants from the China Kadoorie Biobank, whose baseline (2004-2008) blood 25-hydroxyvitamin D had been tested. The average monthly concentrations of pollutants (PM 2.5, PM 10, NO 2, O 3) and the UVR estimates in the month of blood sample collection were derived from the ChinaHighAirPollutants and ultraviolet datasets covering China, respectively. Linear models and multinomial logistic regression models were used to analyze the associations of each air pollutant with vitamin D concentrations and groups. Principal component analysis integrated with quantile-based g-computation was applied to evaluate the co-effects and relative contribution weights of air pollutants. Mediation analyses were performed to investigate the potential role of UVR. Results:PM 2.5, PM 10, NO 2, and O 3 were individually associated with vitamin D concentrations, as well as vitamin D groups: insufficiency (20-30 ng/ml) and deficiency (<20 ng/ml). For each 10 μg/m3 increase in monthly PM 2.5, PM 10, NO 2, and O 3, the percentage changes (95% CIs) in vitamin D concentrations were -1.71% (-2.16% - -1.26%), -1.30% (-1.60% - -1.00%), -3.77% (-4.60% - -2.93%), and 1.27% (0.91%-1.63%), respectively, with corresponding ORs (95% CIs) for vitamin D deficiency of 1.17 (1.06-1.29), 1.12 (1.05-1.19), 1.66 (1.38-2.00), and 0.81 (0.74-0.89). The mixture of the first principal component of PM 2.5 and PM 10 (PM), along with NO 2 and O 3, was negatively correlated with vitamin D. The percentage change (95% CI) in vitamin D concentrations for a one-quintile increase in the mixture was -2.20% (-3.56%- -0.82%), with NO 2 contributing the most (83%), followed by PM (17%). UVR-mediated association was 12.2% (95% CI：2.5%-23.0%) for PM 2.5 and 4.9% (95% CI：2.2%-8.0%) for PM 10 with vitamin D concentrations, respectively. Conclusion:Higher concentrations of particulate matter, NO 2, and a mixture of air pollutants were associated with lower vitamin D concentrations in Chinese adults, with reduced UVR acting as a partial mediator in the particulate matter-vitamin D relationship.

Objective:To investigate the relationship between individual and combined exposure to ambient air pollutants and vitamin D, as well as the potential role of ultraviolet radiation (UVR) in mediating the relationships.Methods:This study included 6 967 participants from the China Kadoorie Biobank, whose baseline (2004-2008) blood 25-hydroxyvitamin D had been tested. The average monthly concentrations of pollutants (PM 2.5, PM 10, NO 2, O 3) and the UVR estimates in the month of blood sample collection were derived from the ChinaHighAirPollutants and ultraviolet datasets covering China, respectively. Linear models and multinomial logistic regression models were used to analyze the associations of each air pollutant with vitamin D concentrations and groups. Principal component analysis integrated with quantile-based g-computation was applied to evaluate the co-effects and relative contribution weights of air pollutants. Mediation analyses were performed to investigate the potential role of UVR. Results:PM 2.5, PM 10, NO 2, and O 3 were individually associated with vitamin D concentrations, as well as vitamin D groups: insufficiency (20-30 ng/ml) and deficiency (<20 ng/ml). For each 10 μg/m3 increase in monthly PM 2.5, PM 10, NO 2, and O 3, the percentage changes (95% CIs) in vitamin D concentrations were -1.71% (-2.16% - -1.26%), -1.30% (-1.60% - -1.00%), -3.77% (-4.60% - -2.93%), and 1.27% (0.91%-1.63%), respectively, with corresponding ORs (95% CIs) for vitamin D deficiency of 1.17 (1.06-1.29), 1.12 (1.05-1.19), 1.66 (1.38-2.00), and 0.81 (0.74-0.89). The mixture of the first principal component of PM 2.5 and PM 10 (PM), along with NO 2 and O 3, was negatively correlated with vitamin D. The percentage change (95% CI) in vitamin D concentrations for a one-quintile increase in the mixture was -2.20% (-3.56%- -0.82%), with NO 2 contributing the most (83%), followed by PM (17%). UVR-mediated association was 12.2% (95% CI：2.5%-23.0%) for PM 2.5 and 4.9% (95% CI：2.2%-8.0%) for PM 10 with vitamin D concentrations, respectively. Conclusion:Higher concentrations of particulate matter, NO 2, and a mixture of air pollutants were associated with lower vitamin D concentrations in Chinese adults, with reduced UVR acting as a partial mediator in the particulate matter-vitamin D relationship.

Objective:To explore the current implementation status and challenges of family doctor contract services (FDCS) from the perspective of contracted residents.Methods:This qualitative study used purposive sampling to select contracted residents from 11 primary healthcare institutions across five cities in China. Semi-structured interviews were conducted from March to December 2024, covering topics such as awareness of contracting, service experience, health needs, service continuity, and policy recommendations. Thematic framework analysis was applied to organize, code, and summarize the data.Results:A total of 25 contracted residents were interviewed (6 men, 19 women; 11 from central urban areas, 14 from suburban or rural towns; 8 with chronic diseases). Three main themes and ten sub-themes emerged: Theme Ⅰ: Pathways to improved service accessibility (optimized chronic disease management, more efficient referrals, and improved health education). Theme Ⅱ: Structural misalignment between supply and demand (limited specialty services despite patient needs, insufficient coverage and public awareness of home-based medical care, imbalanced human resources, and service disruption due to clinician turnover). Theme Ⅲ: Challenges in service awareness and communication mechanisms (information asymmetry and public misperception regarding FDCS, perverse incentives in administrative performance evaluation, and communication barriers in building patient-doctor trust).Conclusions:While FDCS has shown progress in chronic disease management, referral coordination, and health education, structural supply-demand gaps and communication challenges continue to hinder service quality. Improvements in resource allocation and service models are needed to support high-quality development.