The burden of uterine fibroids at global and regional level
Table 1 shows the incident cases, ASR for incidence, prevalent cases, ASR for prevalence, number of YLDs, ASR for YLDs, as well as the net drift. Over the past 30 years, the incident cases increased from 5.77 million to 9.64 million, with growth of 67.07%. Globally in 2019, ASR for incidence was 241.18 (95% UI: 179.45 to 318.02) per 100,000 women, an 6.87% increased from 1990 and the net drift was − 0.04% (95% CI: -0.15 to 0.07) per year. The ASR for incidence in 2019 ranged from 218.56 (95% UI: 162.86 to 287.17) per 100,000 women in middle SDI region to 262.37 (95% UI: 196.04 to 344.26) per 100,000 women in high SDI region. Of the five-SDI regions, two regions (high SDI and high-middle SDI regions) had decreased trend of ASR for incidence from 1990 to 2019 where the largest reduction was in high-middle SDI region with the net drift − 0.54% (95% CI: -0.65 to -0.42) per year. Total of three regions (middle SDI, low-middle SDI and low SDI) showed an upward trend of ASR for incidence from 1990 to 2019 where the highest growth was in low-middle SDI regions with the net drift 0.51% (95% CI: 0.38 to 0.63) per year.
Over the past 30 years, the prevalent cases increased from 126.41 million to 226.05 million, with growth of 78.82%. Globally in 2019, ASR for prevalence was 5467.68 (95% UI: 4210.51 to 6975.18) per 100,000 women, an 1.63% increased from 1990 and the net drift was 0.02% (95% CI: -0.02 to 0.06) per year. The ASR for prevalence in 2019 ranged from 4790.48 (95% UI: 3690.02 to 6152.4) per 100,000 women in middle SDI region to 6325.28 (95% UI: 4924.81 to 7943.16) per 100,000 women in high SDI region. Of the five-SDI regions, two regions (high SDI and high-middle SDI regions) had decreased trend of ASR for prevalence from 1990 to 2019 where the largest reduction was in high-middle SDI region with the net drift − 0.41% (95% CI: -0.45 to -0.36) per year. Total of three regions (middle SDI, low-middle SDI and low SDI) showed an upward trend of ASR for prevalence from 1990 to 2019 where the highest growth was in low-middle SDI regions with the net drift 0.66% (95% CI: 0.63 to 0.69) per year.
The number of YLDs increased from 0.71 million to 1.25 million with growth of 77.34% over the past 30 years. Globally in 2019, ASR for YLDs was 30.32 (95% UI: 14.25 to 56.35) per 100,000 women with an increase of 1.20% and the net drift was 0.01% (95% CI: -0.02 to 0.05) per year. The ASR for YLDs in 2019 ranged from 26.57 (95% UI: 12.5 to 49.39) per 100,000 women in middle SDI region to 34.5 (95% UI: 16.04 to 65.21) per 100,000 women in high SDI region. Of the five-SDI regions, two regions (high SDI and high-middle SDI regions) had decreased trend of ASR for YLDs from 1990 to 2019 where the largest reduction was in high-middle SDI region with the net drift − 0.42% (95% CI: -0.46 to -0.37) per year. Total of three regions (middle SDI, low-middle SDI and low SDI) showed an upward trend of ASR for YLDs from 1990 to 2019 where the highest growth was in low-middle SDI regions with the net drift 0.62% (95% CI: 0.59 to 0.66) per year.
The Burden Of Uterine Fibroids At National Level
Amongst 204 countries and territories, the ASR for incidence ranged from 81.98 to 667.14 per 100,000 women. Latvia (667.14 [95% UI: 492.30 to 884.54] per 100,000 women), Russian Federation (586.64 [95% UI: 434.96 to 771.37] per 100,000 women) and Ukraine (578.21 [95% UI: 427.17 to 766.78] per 100,000 women) had the highest ASR for incidence, while New Zealand (81.98 [95% UI: 62.13 to 104.51] per 100,000 women), Australia (86.13 [95% UI: 62.44 to 114.45] per 100,000 women) and Democratic People's Republic of Korea (103.72 [95% UI: 75.68 to 138.13] per 100,000 women) had the lowest. Of the 204 countries and territories, 186 showed an increasing trend (net drift > 0.0% per year) in ASR for incidence. Brazil (net drift: 1.47% [95% CI: 1.38 to 1.56] per year), India (net drift: 0.89% [95% CI: 0.85 to 0.93] per year) and United States of America (net drift: 0.65% [95% CI: 0.58 to 0.73] per year) showed the largest increases. Poland (net drift: -0.59% [95% CI: -0.67 to -0.51] per year), New Zealand (net drift: -0.37% [95% CI: -0.42 to -0.33] per year) and United Kingdom (net drift: -0.33% [95% CI: -0.40 to -0.26] per year) had the most significant decrease (appendix Figure S1, Table S1).
The ASR for prevalence also varied substantially by country in 2019 (from 1830.67 to 15612.81) per 100,000 women. Latvia (15612.81 [95% UI: 11803.14 to 20170.30] per 100,000 women), Russian Federation (13336.71 [95% UI: 10236.11 to 16959.87] per 100,000 women) and Estonia (13127.11 [95% UI: 9989.26 to 17172.97] per 100,000 women) had the highest ASR for prevalence. In contrast, New Zealand (1830.67 [95% UI: 1451.65 to 2274.51] per 100,000 women), Australia (1915.86 [95% UI: 1449.97 to 2499.94] per 100,000 women) and Democratic People's Republic of Korea (2227.76 [95% UI: 1672.86 to 2904.66] per 100,000 women) showed the lowest. Of the 204 countries and territories, 183 showed an increasing trend (net drift > 0.0% per year) in ASR for prevalence. Brazil (1.03% [95% CI: 0.95 to 1.12] per year), India (0.90% [95% CI: 0.87 to 0.94] per year) and Georgia (0.58% [95% CI: 0.55 to 0.61] per year) showed the largest increasing trend. Poland (-0.58% [95% CI: -0.65 to -0.52] per year), New Zealand (-0.41% [95% CI: -0.47 to -0.36] per year) and United Kingdom (-0.40% [95% CI: -0.43 to -0.36] per year) had the most significant decrease in net drift (Fig. 1, appendix Table S2).
The ASR for YLDs ranged from 9.99 to 85.77 per 100,000 women across the 204 countries and territories in 2019. Latvia (85.77 [95% UI: 39.64 to 163.35] per 100,000 women), Russian Federation (73.12 [95% UI: 33.61 to 141.63] per 100,000 women) and Estonia (72.03 [95% UI: 33.29 to 138.61] per 100,000 women) had the highest ASR for YLDs. In contrast, New Zealand (9.99 [95% UI: 4.67 to 19.00] per 100,000 women), Australia (10.49 [95% UI: 4.72 to 20.48] per 100,000 women) and Democratic People's Republic of Korea (12.54 [95% UI: 5.86 to 23.39] per 100,000 women) showed the lowest. Of the 204 countries and territories, 174 showed an increasing trend (net drift > 0.0% per year) in ASR for YLDs. Brazil (0.99% [95% CI: 0.90 to 1.08] per year), India (0.85% [95% CI: 0.80 to 0.89] per year) and Georgia (0.56% [95% CI: 0.53 to 0.59] per year) showed the largest increasing trends. Poland (-0.59% [95% CI: -0.64 to -0.54] per year), United Kingdom (-0.40% [95% CI: -0.44 to -0.36] per year) and New Zealand (-0.40% [95% CI: -0.45 to -0.35] per year) had the most significant decrease in net drift (appendix Figure S2, Table S3).
Time Trends In Incidence, Prevalence And Ylds Of Uterine Fibroids Across Different Age Groups
Figure 2 showed the annual percentage change in the incidence rate, prevalence rate and YLDs rate of uterine fibroids for each age group, from 10–14 years to 65–69 years in five-year intervals. Globally, the age group from 25–29 years to 45–49 years showed an increasing trend in incidence rate, prevalence rate and YLDs rate, with the highest trend in 35–39 age group (0.27% [95% CI: 0.22 to 0.31] per year; 0.27% [95% CI: 0.22 to 0.31] per year; 0.25% [95% CI: 0.21 to 0.30] per year). After age of 50, the declining trend attenuated with increasing age, with lowest in the oldest age group (-0.48% [95% CI: -0.64 to -0.32] per year; -0.49% [95% CI: -0.63 to -0.34] per year; -0.48% [95% CI: -0.63 to -0.32] per year). Of note, in middle SDI region, low-middle SDI region and low SDI region, uterine fibroids in prevalence rate and YLDs rate had increasing trends across almost all age groups.
Age, Period, And Cohort Effects On Uterine Fibroids Incidence, Prevalence And Ylds
Figure 3, 4, 5 exhibit the estimated effects of age, period and cohort on uterine fibroids incidence, prevalence and YLDs by APC model. Generally, similar patterns in age effects of incidence were found across all SDI regions. In the age group of 10–14 years to 35–39 years, the risk increased with advancing age and peaked at the age of 35–39 years. After age of 40 years, the risk sharply declined with age, with the lowest risk at the oldest age group. Likewise, the age effect of prevalence and YLDs on uterine fibroids was analogously in all SDI regions with increasing risk from 10–14 years (the lowest risk) to 40–44 years and the latter group having the highest risk. After the age of 45, the risk crisply declined with advancing age.
The effects of period effects in incidence, prevalence, and YLDs showed significantly differences across SDI regions over the study period. For high SDI and high-middle SDI countries, period effects presented a declining risk of incidence, prevalence and YLDs during 2005 to 2019 years. On the contrary, period effects showed an increasing risk of incidence, prevalence and YLDs across middle SDI regions, low-middle SDI regions and low SDI region over the past 15 years. Compared with 2000–2004, the RRs of incidence in 2015–2019 ranged from 0.88 (95% CI: 0.83 to 0.94) in high SDI countries to 1.10 (95% CI: 1.08 to 1.13) in low-middle SDI countries. Compared with 2000–2004, the RRs of prevalence in 2015–2019 ranged from 0.92 (95% CI: 0.89 to 0.94) in high-middle SDI to 1.13 (95% CI: 1.12 to 1.14) in low-middle SDI countries. In comparison to 2000–2004, the RRs of YLDs in 2015–2019 ranged from 0.91 (95% CI: 0.90 to 0.92) in high-middle SDI to 1.12 (95% CI: 1.12 to 1.13).
Like the effects of period, the cohort effects on incidence, prevalence, and YLDs across all SDI countries were found significantly differences. Middle SDI countries, low-middle SDI countries and low SDI countries had increasing risk of incidence, prevalence, and YLDs in those born after 1965, whereas the risk in high SDI countries and high-middle SDI countries had little change over different cohorts. Compared with individuals born in the cohort of 1965, the relative cohort risk of incidence for individual born in the 2005 cohort ranged from 1.05 (95% CI: 0.94 to 1.17) in high- middle SDI countries to 1.23 (95% CI: 1.12 to 1.35) in low-middle SDI countries. Compared with individuals born in the cohort of 1965, the relative cohort risk of prevalence for individual born in the 2005 cohort ranged from 1.00 (95% CI: 0.69 to 1.45) in high-middle SDI countries to 1.18 (95% CI: 1.10 to 1.27) in low-middle SDI countries. Compared with individuals born in the cohort of 1965, the relative cohort risk of YLDs for individual born in the 2005 cohort ranged from 0.99 (95% CI: 0.87 to 1.13) in high-middle SDI countries to 1.17 (95% CI: 1.09 to 1.26) in low-middle SDI countries.