PDF
Citation
Print
To the Editor:
We read with great interest the article by Ryu et al.1 as the authors provided valuable findings on the associations between maternal polycystic ovary syndrome (PCOS) and the risk of obesity in female offspring during early childhood. However, we would like to address some key points and share our opinions.
First, the PCOS is a complex disorder characterized by hyperandrogenemia and insulin resistance.2 While women with polycystic ovary syndrome are more prone to obesity, it is noteworthy that only 28% of the Korean women in this study were overweight, which is significantly lower than the 70% observed in Western populations as the authors already proposed. This indicated that the majority of Korean women with PCOS maintain a normal body weight. It is reasonable to infer there may be other underlying causes apart from obesity, such as lifestyle difference and genetic predisposition. Although dietary habit records were inaccessible, as already listed as a limitation by the authors, efforts can still be made to investigate the potential role of genetic factors. Inquiring about relevant family history with possible heritability, such as metabolic disorders including diabetes mellitus in both maternal and paternal family members, can be a feasible approach. It is well-documented that children with a family history of diabetes mellitus, regardless of the paternal or maternal side, pose a higher risk of obesity.3 Thus, obtaining a comprehensive family history of metabolic disease can help overcome this confounding bias.
In addition, there are other contributing factors for obesity in offspring. Both maternal and parental obesity can significantly increase the risk of obesity in their children,4 but this study did not include the information of paternal body mass index (BMI) or obesity. Considering that men typically experience fewer weight fluctuations than women of reproductive age, who are susceptible to hormonal imbalances and the cumulative effects of multiple deliveries, the body weight of fathers should be considered as an important variable when assessing the risk of obesity in their offspring. Another contributing factor is socioeconomic status within the family. A lower education level among caregivers and lower family income are associated with an increased risk of obesity in children.5 Therefore, the stratified analysis by the demographic information about the maternal occupation, salary, or educational background, can help us to find the potential moderator on the risk of childhood obesity. This analysis can also support the development of public health policies aimed at reducing the prevalence of childhood obesity.
Moreover, the inclusion of only participants with sufficient medical records may introduce a bias, as women and their children who underwent thorough examinations often exhibit a higher level of healthcare accessibility, medication adherence, and attention to personal health. Out of all the delivery records in the database for 2007–2008, less than 15% of participants were ultimately enrolled. This substantial reduction in the remaining sample size raises concerns about the selection bias, that results in inaccurately representing the diverse population under investigation.
The last concern that remains unclear to us is the absence of the exact number of children who participated in the 5th, 6th, and 7th screenings, during which BMI of offspring was exclusively recorded. This information is especially important, as the children’s BMI serves as a crucial outcome measure in this study. This lack of transparency and missing data weakens the reliability and validity of the study. Revealing the number of children in each of the three groups in Tables 2, 3, and 4 would enhance the credibility of this study.
Despite these minor deficiencies mentioned above, the conclusion of this study is highly valuable as it emphasizes the distinctive connection between mothers and daughters. It should be taken seriously that women with polycystic ovary syndrome should closely monitor the health of their children, particularly their daughters, who may encounter an elevated risk of obesity starting from an early age. Further discussions are required to reduce the impact of potential biases, leading to more reliable research on the association between maternal polycystic ovary syndrome and health issues in offspring.
Authors' Response to the Letter
To the Editor:
Thank you for the opportunity to respond to the letter submitted by Chen et al. We are thankful for their interest in our study.
Chen et al. requested additional information about the number of children who participated in the 5th, 6th, and 7th screenings during which BMI of offspring was exclusively recorded in the NHSP-IC database. The number of male offspring was 39,769, 37,495, and 35,891, and that of female offspring was 37,563, 36,115, and 34,252, in those three groups, respectively.
As reported in our article, only 28% of Korean women with PCOS were overweight/obese in our study, which is significantly lower than the 70% observed in Western populations in the previous studies.1 It has been well studied that there is considerable ethnic variation in the manifestation of PCOS, and previous studies have reported a low BMI and mild hirsutism in East Asian women with PCOS compared to that in Western or South Asian women with PCOS.67 Our findings suggest that Korean women with PCOS should consider the probable early childhood obesity of their female offspring, even if they are not obese, and maintain healthy weight. Those results were adjusted for the metabolic confounding factors of mothers including BMI, blood pressure, high liver function test, high total cholesterol, smoking, hypertension, diabetes, gestational diabetes, hypertensive disorders in pregnancy.1 As pointed out by Chen et al., including a more detailed family history of metabolic disorders in the analysis may help to confirm the above findings. However, in the studies using routine health check-up data, information on family history of metabolic diseases would be limited and there are concerns that it may not be accurate. Further prospective cohort study will be needed to compensate for the above limitation.
As mentioned by Chen et al., in determining a child's risk of obesity, not only the mother’s obesity, but also the father’s obesity is important. Although we were able to connect and analyze the mother’s information and their offspring’s checkup result information using NHIS database, there were limitations in identifying and linking the father’s information as well. The result of this study that the mother's history of PCOS affects the female offspring’s obesity has important clinical significance. To confirm those findings, as suggested by Chen et al., it would be helpful to additionally analyze father’s weight information and mother’s social information such as occupation and income levels, which can be accurately obtained and analyzed through a prospective cohort study. Furthermore, it is expected that through future studies, the inherent limitations of research using the nationwide insurance database, such as selection bias, as pointed out by Chen et al., can be supplemented. We would like to thank Chen et al. for the interest in our study and insightful recommendations for future research direction.
Ki-Jin Ryu,1 Won Young Wi,2 Seunghyun Nam,1 Hye Gyeong Jeong,1 Geum Joon Cho,2 Hyuntae Park,1 and Tak Kim1
1Department of Obstetrics and Gynecology, Korea University Anam Hospital, Korea University College of Medicine, Seoul, Korea.
2Department of Obstetrics and Gynecology, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Republic of Korea.
Address for Correspondence: Geum Joon Cho, MD, PhD. Department of Obstetrics and Gynecology, Korea University Guro Hospital, Korea University College of Medicine, 73 Goryeodae-ro, Seongbuk-gu, Seoul 02841, Korea. md_cho@hanmail.net
Address for Correspondence: Hyuntae Park, MD, PhD. Department of Obstetrics and Gynecology, Korea University Anam Hospital, Korea University College of Medicine, 73 Goryeodae-ro, Seongbuk-gu, Seoul 02841, Korea. cyberpelvi@korea.ac.kr
XML Download