Frequencies of thyroid-related diagnoses and dyslipidemia among Japanese women with menstrual-related disorders aged under 40 years: A nationwide cross-sectional study using health insurance claims data
- 1Department of Obstetrics and Gynecology, University of Yamanashi, Yamanashi, Japan.
- 2Rohto Pharmaceutical Co., Ltd., Osaka, Japan.
Abstract
Women with endometriosis and dysmenorrhea are increasingly recognized as having systemic comorbidities beyond pelvic disease, but large-scale data on endocrine and metabolic comorbidities across a broad menstrual-related disorders population remain limited. Using the Japan Medical Data Center Claims Database, we conducted a nationwide cross-sectional study of women aged under 40 years enrolled in 2023. Women with confirmed diagnoses of endometriosis (ICD-10: N80) and/or dysmenorrhea (N94.4 or N94.6) were classified as the menstrual-related disorders group (n = 257,897); those without such diagnoses were the control group (n = 3,183,032). The primary outcomes were the frequencies of thyroid-related diagnoses (hypothyroidism [E03], non-toxic goiter [E04], hyperthyroidism [E05], thyroiditis [E06], and other thyroid disorders [E07]) and dyslipidemia (E78). Stratified analyses were performed according to prescription for low-dose estrogen–progestin preparations (LEP) or dienogest (DNG). All thyroid-related diagnoses were recorded more frequently among women with menstrual-related disorders than among controls. Hypothyroidism was identified in 2.1% of women with menstrual-related disorders versus 0.8% of controls (prevalence ratio [PR] 2.46; 95% CI 2.39–2.54); the corresponding PR was 3.11 (95% CI 2.99–3.24) in the endometriosis subgroup (n = 96,863). Dyslipidemia was recorded in 5.2% of women with menstrual-related disorders versus 1.4% of controls (PR 3.73; 95% CI 3.66–3.80; prevalence difference +3.78 percentage points). The endometriosis subgroup consistently showed the highest frequencies. These associations remained statistically significant after adjustment for age using the Mantel-Haenszel method (adjusted PR 1.45–3.02 across all comparisons), although adjusted estimates were consistently lower than crude estimates. Among women with menstrual-related disorders, hypothyroidism was more frequent in those without LEP/DNG prescriptions (3.4%) than in those with prescriptions (1.5%), whereas dyslipidemia frequencies were similar (5.2% vs. 5.1%). These findings indicate that young Japanese women with menstrual-related disorders have substantially higher frequencies of thyroid-related diagnoses and dyslipidemia than controls, particularly those with endometriosis. Surveillance bias, age confounding, and confounding by indication cannot be excluded because of the cross-sectional claims-based design.
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BibTeX
@article{yoshihara2026frequencies,
title = {{Frequencies of thyroid-related diagnoses and dyslipidemia among Japanese women with menstrual-related disorders aged under 40 years: A nationwide cross-sectional study using health insurance claims data}},
author = {Tatsuya Yoshihara and Yosuke Ono and Harumasa Arita and Akiko Nakagomi and Dai Miyashita and Kota Tanaka and Satoko Sasatsu and Osamu Yoshino},
journal = {PLOS One},
year = {2026},
month = oct,
doi = {10.1371/journal.pone.0361575},
url = {https://doi.org/10.1371/journal.pone.0361575},
note = {CC BY},
}
RIS
TY - JOUR
TI - Frequencies of thyroid-related diagnoses and dyslipidemia among Japanese women with menstrual-related disorders aged under 40 years: A nationwide cross-sectional study using health insurance claims data
AU - Tatsuya Yoshihara
AU - Yosuke Ono
AU - Harumasa Arita
AU - Akiko Nakagomi
AU - Dai Miyashita
AU - Kota Tanaka
AU - Satoko Sasatsu
AU - Osamu Yoshino
PY - 2026
DA - 2026/10/30
JO - PLOS One
DO - 10.1371/journal.pone.0361575
UR - https://doi.org/10.1371/journal.pone.0361575
AB - Women with endometriosis and dysmenorrhea are increasingly recognized as having systemic comorbidities beyond pelvic disease, but large-scale data on endocrine and metabolic comorbidities across a broad menstrual-related disorders population remain limited. Using the Japan Medical Data Center Claims Database, we conducted a nationwide cross-sectional study of women aged under 40 years enrolled in 2023. Women with confirmed diagnoses of endometriosis (ICD-10: N80) and/or dysmenorrhea (N94.4 or N94.6) were classified as the menstrual-related disorders group (n = 257,897); those without such diagnoses were the control group (n = 3,183,032). The primary outcomes were the frequencies of thyroid-related diagnoses (hypothyroidism [E03], non-toxic goiter [E04], hyperthyroidism [E05], thyroiditis [E06], and other thyroid disorders [E07]) and dyslipidemia (E78). Stratified analyses were performed according to prescription for low-dose estrogen–progestin preparations (LEP) or dienogest (DNG). All thyroid-related diagnoses were recorded more frequently among women with menstrual-related disorders than among controls. Hypothyroidism was identified in 2.1% of women with menstrual-related disorders versus 0.8% of controls (prevalence ratio [PR] 2.46; 95% CI 2.39–2.54); the corresponding PR was 3.11 (95% CI 2.99–3.24) in the endometriosis subgroup (n = 96,863). Dyslipidemia was recorded in 5.2% of women with menstrual-related disorders versus 1.4% of controls (PR 3.73; 95% CI 3.66–3.80; prevalence difference +3.78 percentage points). The endometriosis subgroup consistently showed the highest frequencies. These associations remained statistically significant after adjustment for age using the Mantel-Haenszel method (adjusted PR 1.45–3.02 across all comparisons), although adjusted estimates were consistently lower than crude estimates. Among women with menstrual-related disorders, hypothyroidism was more frequent in those without LEP/DNG prescriptions (3.4%) than in those with prescriptions (1.5%), whereas dyslipidemia frequencies were similar (5.2% vs. 5.1%). These findings indicate that young Japanese women with menstrual-related disorders have substantially higher frequencies of thyroid-related diagnoses and dyslipidemia than controls, particularly those with endometriosis. Surveillance bias, age confounding, and confounding by indication cannot be excluded because of the cross-sectional claims-based design.
SN - 1932-6203
ER -