Although HIV caused one of the worst epidemics since the late twentieth century, China and the U.S. has made substantial progress to control the spread of HIV/AIDS. However, the trends of HIV/AIDS incidence remain unclear in both countries. Therefore, this study aimed to highlight the long-term trends of HIV/AIDS incidence by gender in China and the U.S. population. The data were retrieved from the Global Burden of Disease (GBD) database since it would be helpful to assess the impact/role of designed policies in the control of HIV/AIDS incidence in both countries. The age-period-cohort (APC) model and join-point regression analysis were employed to estimate the age-period-cohort effect and the average annual percentage change (AAPC) on HIV incidence. Between 1994 and 2019, we observed an oscillating trend of the age-standardized incidence rate (ASIR) in China and an increasing ASIR trend in the U.S. Despite the period effect in China declined for both genders after peaked in 2004, the age effect in China grew among the young (from 15–19 to 25–29) and the old age groups (from 65–69 to 75–79). Similarly, the cohort effect increased among those born in the early (from 1924–1928 to 1934–1938) and the latest birth groups (from 1979–1983 to 2004–2009). In the case of the U.S., the age effect declined after it peaked in the 25–29 age group. People born in recent birth groups had a higher cohort effect than those born in early groups. In both countries, women were less infected by HIV than men. Therefore, besides effective strategies and awareness essential to protect the young age groups from HIV risk factors, the Chinese government should pay attention to the elderly who lacked family support and were exposed to HIV risk factors.

Background The incidence rate of type 2 diabetes mellitus (T2DM) is rapidly increasing in Brazil, Russia, India, China, and South Africa (BRICS). The present study analyzed trends in T2DM incidence rate across the BRICS and associations with age, period, and birth cohort. Methods The incidence rate was estimated by the data obtained from GBD 2019 (Global Burden of Disease Study 2019) and was analyzed with the age-period-cohort framework. Incidence rates of T2DM (1990–2019) were collected for each 5-year age group (from 25 to 29 to 85–89 age group) stratified by gender from the Global Burden of Disease 2019 Study. Results In 2019, the the incidence rate of T2DM was 280.2 per 100,000 across the BRICS. Between 1990 and 2019, the incidence rate of T2DM among the BRICS population increased by 83.3%. In each period, as age increases, the incidence rate of T2DM in China and Russia first increased and then decreased, while the incidence rate of T2DM in Brazil, India and South Africa first increased and then decreased slightly with age group. Deteriorating period and cohort risks for incidence rate of T2DM were generally found across the BRICS. Conclusions The number of diabetic patients in the BRICS countries has continued to increase and the growth rate has been stable in the past 30 years, which is dependent on age and some other environmental factors. Some possible factors influencing T2DM incidence are analyzed and hypotheses generated through the age and period effects.

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Background As the emerging economies, the BRICS (Brazil, Russia, India, China, and South Africa) shared 61.58% of the global chronic respiratory diseases (CRD) deaths in 2017. This study aimed to assess the secular trends in CRD mortality and explore the effects of age, period, and cohort across main BRICS countries. Methods Data were obtained from the Global Burden of Disease Study (GBD) 2019 and analyzed using the age-period-cohort (APC) model to estimate period and cohort effects between 1990 and 2019. The net drifts, local drifts, longitudinal age curves, period/cohort rate ratios (RRs) were obtained through the APC model. Results In 2019, the CRD deaths across the BRICS were 2.39 (95%UI 1.95 to 2.84) million, accounting for 60.07% of global CRD deaths. Chronic obstructive pulmonary disease (COPD) and asthma remained the leading causes of CRD deaths. The age-standardized mortality rates (ASMR) have declined across the BRICS since 1990, with the most apparent decline in China. Meanwhile, the downward trends in CRD death counts were observed in China and Russia. The overall net drifts per year were obvious in China (-5.89%; -6.06% to -5.71%), and the local drift values were all below zero in all age groups for both sexes. The age effect of CRD presented increase with age, and the period and cohort RRs were following downward trends over time across countries. Similar trends were observed in COPD and asthma. The improvement of CRD mortality was the most obvious in China, especially in period and cohort effects. While South Africa showed the most rapid increase with age across all CRD categories, and the period and cohort effects were flat. Conclusions BRICS accounted for a large proportion of CRD deaths, with China and India alone contributing more than half of the global CRD deaths. However, the declines in ASMR and improvements of period and cohort effects have been observed in both sexes and all age groups across main BRICS countries. China stands out for its remarkable reduction in CRD mortality and its experience may help reduce the burden of CRD in developing countries.