Overall trends of diseases burden of FBTs from 1990 to 2021

In 2021, the worldwide number of FBTs cases [including clonorchiasis, fascioliasis, fasciolopsiasis (intestinal fluke), opisthorchiasis, and paragonimiasis] was 44,466,329 [95% uncertainty interval (UI): 40,017,217, 50,034,921], with an ASPR of 526.74 (95% UI: 473.70, 593.25) (Table 1). In 2021, the global DALYs for FBTs were 998,028 (95% UI: 569,766, 1,638,112), and the ASDR were 11.78 (95% UI: 6.72, 19.46), representing a reduction of 2.40 (95% UI: − 2.60, − 2.30) from 1990 to 2021. The prevalence of FBTs is higher in males than in females with 26,792,503 cases in males (95% UI: 23,935,772, 30,187,221) and 17,673,826 cases in females (95% UI: 15,992,365, 19,815,428) in 2021.

Table 1 Crude number and age-standardized rates (per 100,000 population) of prevalent cases and DALYs attributable to FBTs in 2021 by gender, SDI and county

Joinpoint regression analysis revealed substantial changes in the DALYs trends of worldwide FBTs in 1995, 2005, 2010, 2015, 2019. Notably, a significant decline was observed during four periods: from 1990 to 1995 (AAPC = − 5.24, 95% CI: − 5.60, − 4.90, P < 0.05), from 1995 to 2005 (AAPC = − 1.93, 95% CI: − 2.10, − 1.80, P < 0.05), from 2005 to 2010 (AAPC = − 3.54, 95% CI: − 3.90, − 3.10, P < 0.05), from 2015 to 2019 (AAPC = − 9, 95% CI: − 9.60, − 8.40, P < 0.05). However, a sudden increase in the ASDR of FBTs was observed from 2010 to 2015 (AAPC = 5.94, 95% CI: 5.00, 5.90, P < 0.05). The increase in ASDR for males (AAPC = 6.49, 95% CI: 6.10, 6.90, P < 0.05) was faster than that for females (AAPC = 4.00, 95% CI: 3.40, 4.60, P < 0.05) from 2010 to 2015 (Table 1, Fig. 1).

Fig. 1

APC of ASDR for FBTs (per 100,000 population) at the global level with different gender from 1990 to 2021. Yellow line: APC of ASDR for FBTs in male; blue line: APC of ASDR for FBTs in Both gender. dark blue line: APC of ASDR for FBTs in female, * represents P < 0.05, APC annual percentage change, ASDR age-standardized DALY rate, FBTs food-borne trematodiases

Geographical variation and temporal trends in the diseases burden of FBTs at regional and national levels

The geographical distribution of AAPC for DALYs from 1990 to 2021 is shown in Table 1, Fig. 2 and Additional file: Table S1. The Western Pacific Region consistently has the highest number of cases from 1990 (40,392,544 cases) to 2021 (38,096,830 cases), showing fluctuations, particularly a significant dip around 2005, followed by an increase from 2010 to 2015, and a decline afterward. (Fig. 2A, and Table 1). Compared to 1990, the age-standardized rates of prevalence and DALYs have decreased in all regions. Among the six regions, South-East Asia region experienced the greatest decrease, dropping from 7,603,462 cases in 1990 to 1,896,042 cases in 2021, with a decrease rate of 75.00% (Fig. 2B). However, compared to 1990, the crude cases of prevalence of FBTs in 2021 increased by 58.05% in the Region of the Americas, 49.51% in the Eastern Mediterranean Region, and 0.85% in the European Region, respectively.

Fig. 2

Temporal variation in ASDR of FBTs (per 100,000 population) at the WHO regional level. A ASDR of FBTs at WHO regional levels from 1990 to 2021, B ASDR of FBTs at the WHO regional level in 1990 and 2021. ASDR age-standardized DALYs rate, FBTs food-borne trematodiases

As is shown in Fig. 2B, the region with the second highest ASDR ranking changed from the South-East Asia region in 1990 to the European region in 2021.

When stratified by individual nations, it was found that 17 countries have FBTs cases world widely. In 2021, the four countries with the highest number of cases are P.R. China, Thailand, Republic of Korea and Vietnam, which together account for 84.74% of the global FBT cases. Meanwhile, six countries had DALYs greater than 40, listed from highest to lowest: Lao People’s Democratic Republic (Lao PDR), Bolivia (Plurinational State of), Peru, Thailand, Republic of Korea, and P.R. China. As is shown in Table 1, from the overall trend between 1990 and 2021, 13 countries showed a decrease in the AAPC of DALYs of FBTs from 1990 to 2021, with the largest decrease in Kazakhstan (AAPC = − 6.60, 95% CI: − 7.10, − 6.10, P < 0.05). As shown in Fig. 3, between 2006 and 2010, the significant phase of decline (P < 0.05) in ASDR for FBTs occurred in Kazakhstan (APC = − 20.80, 95% CI: − 22.40, − 19.20, P < 0.05), Ecuador (APC = − 12.50, 95% CI: − 13.00, − 12.00, P < 0.05), Portugal (APC = − 13.40, 95% CI: − 13.60,− 13.20, P < 0.05), Lao PDR (APC = − 12.40, 95% CI: − 12.80, − 12.10, P < 0.05). The largest increase in the ASDR for FBTs from 1990 to 2021 was in Iran (Islamic Republic of) (AAPC = 2.60, 95% CI: 2.50, 2.60, P < 0.05), followed by Ukraine (AAPC = 2.10, 95% CI: 1.70, 2.60), Spain (AAPC = 2.10, 95% CI: 2.00, 2.20, P < 0.05) and Japan (AAPC = 1.10, 95% CI: 1.00, 1.10, P < 0.05). Notably, from 2001 to 2012, a rapid and sustained increased in the ASDR was observed in Ukraine (APC = 10.12, 95% CI: 9.20, 11.00, P < 0.05), continuing an upward trend after 2012. An increase occurred in the ASDR of FBTs in Republic of Korea from 2010 to 2015 (APC = 4.20, 95% CI: 4.10, 4.40, P < 0.05).

Fig. 3

APC of ASDR for FBTs (per 100,000 population) at the country level from 1990 to 2021. APC annual percentage change; * represents P < 0.05, ASDR age-standardized DALYs rate, FBTs food-borne trematodiases

National burden trends for FBTs ASDR among SDI quintiles

Among the 17 countries with ASDR association from 1990 to 2021, a negative association was found among ASDR and SDI (r = − 0.34, P < 0.05) (Fig. 4A). DALYs declined in many countries as SDI increased, except in certain countries like Ukraine and Republic of Korean, where the ASDR increased with higher SDI. The top two countries with the highest DALYs, Lao PDR and Bolivia (Plurinational State of), have low-middle SDI. Regions with middle SDI (28.03; 95% UI: 15.42, 48.73) and high-middle SDI (16.64; 95% UI: 9.32, 27.68) had higher ASDR than other regions (Fig. 4B, Table 1).

Fig. 4

ASDR of FBTs and SDI by country from 1990 to 2021. ASDR of FBTs per 100,000 population (A) and SDI for 17 countries from 1990 to 2021 and (B) in 2021 is shown. Points represent 1 year increment from 1990 to 2021. The blue line represents the correlation between ASDR and SDI, with a correlation coefficient of − 0.34 (P < 0.05). ASDR age-standardized DALY rate, FBTs food-borne trematodiases, SDI sociodemographic index

Age-period-cohort effects on prevalence rate of FBTs

The effects of age, period and cohort on the prevalence rate of FBTs were explored based on age-period cohort analysis (Fig. 5). The prevalence of FBTs increased with age, reaching a peak in the 55–59 age group, then decreased. The period effect curve shows a slight downward trend. The cohort effect reveals that cohorts born before 1975–1979 have a higher risk of disease, which then declines, but the risk starts to increase again for cohorts born after 1995–1999 (Additional file: Table S2).

Fig. 5

Effects of age, period and cohort on the prevalence of FBTs globally

Projections of FBTs burden from 2022 to 2030

Generally, the ASDR is projected to remain stable with a slight decline in the coming years based on the BAPC model (see Fig. 6). The ASDR in males is predicted to decrease to approximately 13.10 in 2030 (Fig. 6A). Similarly, the ASDR in females is predicted to decrease slightly after 2021, reaching approximately 8.40 in 2030 (Additional file: Table S3).

Fig. 6

Prediction of ASDR for FBTs worldwide from 2022 to 2030 in males (A) and females (B) based on BAPC models. A ASDR for FBTs worldwide in males, B ASDR for FBTs worldwide in females. ASDR age-standardized DALY rate, FBTs food-borne trematodiases, BAPC Bayesian age-period-cohort