International journal of epidemiology最新文献

Background: By mid-2024, >13 billion COVID-19 vaccine doses had been administered globally, with totals continuing to rise into 2025, yet persistent inequities remain in low- and middle-income countries (LMICs). We examined spatial determinants of COVID-19 vaccination uptake (proportion of eligible persons vaccinated) in Kenya by using the most recent nationally representative survey, the Kenya Demographic and Health Survey 2022. Our central contribution is the detection of seven spatially concentrated vulnerability clusters, complemented by using a Development Index (DI) and equity auditing to guide targeted action.

Methods: We integrated socioeconomic, healthcare, environmental, and demographic measures at the Demographic and Health Survey cluster level; quantified spatial dependence (Moran's I; spatial lag models); identified socio-geographic clusters (K-means); estimated variable importance (random forest); and synthesized a DI. Equity was assessed by using the Erreygers Concentration Index (ECI) along two axes: wealth-based (poorest→richest) and immunization-linked (lowest→highest routine child immunization coverage).

Results: Our results reveal stark geographic disparities: vaccination rates range from 5.93% in Garissa to 46.02% in Nyeri, with urban clusters achieving significantly higher uptake. Key predictors include bank access (financial inclusion), household crowding, and environmental factors (nitrogen dioxide levels, precipitation). The DI correlated positively with uptake and the ECI indicated modest immunization-linked inequality and more pronounced wealth-related inequality.

Conclusion: This study underscores the need for targeted interventions, including mobile vaccination units, financial inclusion programs (e.g. M-Pesa subsidies), and the integration of COVID-19 vaccines into routine immunization programs. As Kenya and many LMICs integrate COVID-19 vaccination into routine immunization, our spatial approach, combining DI, cluster detection, and equity metrics, provides an operational toolkit to prioritize underserved areas, inform the placement of service points/mobile teams, and monitor equity as programs transition from campaigns to routine delivery.

Background: The age of puberty is declining. Earlier puberty has major implications due to associations with later physiological and psychiatric morbidities. Therefore, the identification of potential modifiable risk factors is warranted. The Puberty Cohort, nested within the Danish National Birth Cohort (DNBC), was set up to identify the causes and consequences of earlier puberty and to establish whether age at puberty is still declining.

Methods: The DNBC Puberty Cohort consists of 15 819 live-born singletons (8123 girls and 7696 boys) born in 2000-03. From 2012 to 2021, they provided information on several pubertal milestones half-yearly from ages 11 to 18 years. In this review, we present the results from the studies conducted in the DNBC Puberty Cohort so far addressing the importance of prenatal and childhood biological and psychosocial factors.

Results: Age at puberty is still declining among Danish girls and boys. Several risk factors for earlier puberty have been identified, including familial predisposition, childhood overweight and obesity, maternal smoking in the first trimester, several maternal gestational diseases, as well as psychosocial exposures. The mentioned exposures were associated with earlier puberty of ≤4-5 months in both girls and boys. Other exposures studied showed either weaker or no association with earlier puberty, but for some also later puberty.

Conclusion: Ten years of research within the unique DNBC Puberty Cohort has identified several prenatal and childhood biological and psychosocial factors associated with earlier puberty, including potential targets for intervention both during pregnancy and in childhood.

Background: Epidemiological studies evaluating the potential association between oral contraceptive (OC) use and melanoma risk have reported conflicting results. We assessed the association of OC use with melanoma risk in a large prospective cohort.

Methods: The Nightingale Study comprises 59 944 Dutch female nurses at ages 19-65 years (mean, 46.9 years; SD, 11.0) who completed a baseline questionnaire in 2011, including information on lifetime OC use. Melanoma incidence was retrieved through linkage with the Netherlands Cancer Registry. Associations between lifetime OC use and risk of melanoma were assessed by using Cox proportional hazard models. Women who used OCs at baseline were considered current users and women who had used OCs but stopped before baseline were considered former users. Never OC users were defined as the reference.

Results: During 10 years of follow-up, 447 women were diagnosed with melanoma. Melanoma risk was not increased among women who used OCs for a duration of <9, 10-15, or ≥16 years compared with never CO users. Melanoma risk was increased for current OC users [hazard ratio (HR), 1.53; 95% confidence interval (CI), 1.03-2.29], without a trend with duration of use (P-trend = .42) and age at cohort entry (P-trend = .05). Melanoma risk was not increased among former OC users (HR, 0.99; 95% CI, 0.72-1.38) nor when they had last used OC <2 years before baseline (HR, 0.69; 95% CI, 0.36-1.32).

Conclusion: Current OC use was associated with increased melanoma risk, irrespective of the duration or recency of use.