Genome- and transcriptome-wide association studies of 386,000 Asian and European-ancestry women provide new insights into breast cancer genetics.

By combining data from 160,500 individuals with breast cancer and 226,196 controls of Asian and European ancestry, we conducted genome- and transcriptome-wide association studies of breast cancer. We identified 222 genetic risk loci and 137 genes that were associated with breast cancer risk at a p < 5.0 × 10-8 and a Bonferroni-corrected p < 4.6 × 10-6, respectively. Of them, 32 loci and 15 genes showed a significantly different association between ER-positive and ER-negative breast cancer after Bonferroni correction. Significant ancestral differences in risk variant allele frequencies and their association strengths with breast cancer risk were identified. Of the significant associations identified in this study, 17 loci and 14 genes are located 1Mb away from any of the previously reported breast cancer risk variants. Pathways analyses including 221 putative risk genes identified multiple signaling pathways that may play a significant role in the development of breast cancer. Our study provides a comprehensive understanding of and new biological insights into the genetics of this common malignancy.

Differential patterns of reproductive and lifestyle risk factors for breast cancer according to birth cohorts among women in China, Japan and Korea.

BACKGROUND: The birth cohort effect has been suggested to influence the rate of breast cancer incidence and the trends of associated reproductive and lifestyle factors. We conducted a cohort study to determine whether a differential pattern of associations exists between certain factors and breast cancer risk based on birth cohorts. METHODS: This was a cohort study using pooled data from 12 cohort studies. We analysed associations between reproductive (menarche age, menopause age, parity and age at first delivery) and lifestyle (smoking and alcohol consumption) factors and breast cancer risk. We obtained hazard ratios (HRs) with 95% confidence intervals (CIs) using the Cox proportional hazard regression analysis on the 1920s, 1930s, 1940s and 1950s birth cohorts. RESULTS: Parity was found to lower the risk of breast cancer in the older but not in the younger birth cohort, whereas lifestyle factors showed associations with breast cancer risk only among the participants born in the 1950s. In the younger birth cohort group, the effect size was lower for parous women compared to the other cohort groups (HR [95% CI] 0.86 [0.66-1.13] compared to 0.60 [0.49-0.73], 0.46 [0.38-0.56] and 0.62 [0.51-0.77]). Meanwhile, a higher effect size was found for smoking (1.45 [1.14-1.84] compared to 1.25 [0.99-1.58], 1.06 [0.85-1.32] and 0.86 [0.69-1.08]) and alcohol consumption (1.22 [1.01-1.48] compared to 1.10 [0.90-1.33], 1.15 [0.96-1.38], and 1.07 [0.91-1.26]). CONCLUSION: We observed different associations of parity, smoking and alcohol consumption with breast cancer risk across various birth cohorts.

Association between family history with lung cancer incidence and mortality risk in the Asia Cohort Consortium.

Family history of lung cancer (FHLC) has been widely studied but most prospective cohort studies have primarily been conducted in non-Asian countries. We assessed the association between FHLC with risk of lung cancer (LC) incidence and mortality in a population of East Asian individuals. A total of 478,354 participants from 11 population-based cohorts in the Asia Cohort Consortium were included. A Cox proportional hazards regression model was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). A total of 7,785 LC incident cases were identified. FHLC (any LC subtype) was associated with an increased risk of LC incidence (HR = 1.45, 95% CI = 1.30-1.63). The positive association was observed in men and women (HR = 1.44, 95% CI = 1.26-1.66 in men; HR = 1.47, 95% CI = 1.22-1.79 in women), and in both never-smokers and ever-smokers (HR = 1.43, 95% CI = 1.18-1.73 in never-smokers; HR = 1.46, 95% CI =1.27-1.67 in ever-smokers). FHLC was associated with an increased risk of lung adenocarcinoma (HR = 1.63, 95% CI: 1.36-1. 94), squamous cell carcinoma (HR = 1.88, 95% CI: 1.46-2.44), and other non-small cell LC (HR = 1.94, 95% CI: 1.02-3.68). However, we found no evidence of significant effect modification by sex, smoking status, and ethnic groups. In conclusion, FHLC was associated with increased risk of LC incidence and mortality, and the associations remained consistent regardless of sex, smoking status and ethnic groups among the East Asian population.

Association between reproductive factors with lung cancer incidence and mortality: A pooled analysis of over 308,000 females in the Asia cohort consortium.

Previous studies have investigated the association between reproductive factors and lung cancer risk; however, findings have been inconsistent. In order to assess this association among Asian women, a total of 308,949 female participants from 11 prospective cohorts and four Asian countries (Japan, Korea, China, and Singapore) were included. Cox proportional hazards regression models were used to estimate the hazard ratios (HR) and 95% confidence intervals (CIs). A total of 3,119 primary lung cancer cases and 2247 lung cancer deaths were identified with a mean follow-up of 16.4 years. Parous women had a lower risk of lung cancer incidence and mortality as compared with nulliparous women, with HRs of 0.82 (95% CI = 0.70-0.96) and 0.78 (95% CI = 0.65-0.94). The protective association of parity and lung cancer incidence was greater among ever-smokers (HR = 0.66, 95% CI = 0.49-0.87) than in never-smokers (HR = 0.90, 95% CI = 0.74-1.09) (P-interaction = 0.029). Compared with age at first delivery ≤20 years, older age at first delivery (21-25, ≥26 years) was associated with a lower risk of lung cancer incidence and mortality. Women who ever used hormone replacements had a higher likelihood of developing non-small cell lung cancer (HR = 1.31, 95% CI = 1.02-1.68), compared to those who never used hormone replacements. Future studies are needed to assess the underlying mechanisms, the relationships within these female reproductive factors, and the potential changes in smoking habits over time.

Association of female reproductive and hormonal factors with gallbladder cancer risk in Asia: A pooled analysis of the Asia Cohort Consortium.

The female predominance of gallbladder cancer (GBC) has led to a hypothesis regarding the hormone-related aetiology of GBC. We aimed to investigate the association between female reproductive factors and GBC risk, considering birth cohorts of Asian women. We conducted a pooled analysis of 331,323 women from 12 cohorts across 4 countries (China, Japan, Korea, and Singapore) in the Asia Cohort Consortium. Cox proportional hazard models were used to estimate the hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) to assess the association between reproductive factors (age at menarche, parity, age at first delivery, breastfeeding, and age at menopause) and GBC risk. We observed that a later age at menarche was associated with an increased risk of GBC (HR 1.4, 95% CI 1.16-1.70 for 17 years and older vs. 13-14 years), especially among the cohort born in 1940 and later (HR 2.5, 95% CI 1.50-4.35). Among the cohort born before 1940, women with a later age at first delivery showed an increased risk of GBC (HR 1.56, 95% CI 1.08-2.24 for 31 years of age and older vs. 20 years of age and younger). Other reproductive factors did not show a clear association with GBC risk. Later ages at menarche and at first delivery were associated with a higher risk of GBC, and these associations varied by birth cohort.

Obesity is associated with biliary tract cancer mortality and incidence: A pooled analysis of 21 cohort studies in the Asia Cohort Consortium.

Body fatness is considered a probable risk factor for biliary tract cancer (BTC), whereas cholelithiasis is an established factor. Nevertheless, although obesity is an established risk factor for cholelithiasis, previous studies of the association of body mass index (BMI) and BTC did not take the effect of cholelithiasis fully into account. To better understand the effect of BMI on BTC, we conducted a pooled analysis using population-based cohort studies in Asians. In total, 905 530 subjects from 21 cohort studies participating in the Asia Cohort Consortium were included. BMI was categorized into four groups: underweight (<18.5 kg/m2 ); normal (18.5-22.9 kg/m2 ); overweight (23-24.9 kg/m2 ); and obese (25+ kg/m2 ). The association between BMI and BTC incidence and mortality was assessed using hazard ratios (HR) and 95% confidence intervals (CIs) by Cox regression models with shared frailty. Mediation analysis was used to decompose the association into a direct and an indirect (mediated) effect. Compared to normal BMI, high BMI was associated with BTC mortality (HR 1.19 [CI 1.02-1.38] for males, HR 1.30 [1.14-1.49] for females). Cholelithiasis had significant interaction with BMI on BTC risk. BMI was associated with BTC risk directly and through cholelithiasis in females, whereas the association was unclear in males. When cholelithiasis was present, BMI was not associated with BTC death in either males or females. BMI was associated with BTC death among females without cholelithiasis. This study suggests BMI is associated with BTC mortality in Asians. Cholelithiasis appears to contribute to the association; and moreover, obesity appears to increase BTC risk without cholelithiasis.

Diabetes is associated with increased liver cancer incidence and mortality in adults: A report from Asia Cohort Consortium.

There has been growing evidence suggesting that diabetes may be associated with increased liver cancer risk. However, studies conducted in Asian countries are limited. This project considered data of 968,738 adults pooled from 20 cohort studies of Asia Cohort Consortium to examine the association between baseline diabetes and liver cancer incidence and mortality. Cox proportional hazard model and competing risk approach was used for pooled data. Two-stage meta-analysis across studies was also done. There were 839,194 subjects with valid data regarding liver cancer incidence (5654 liver cancer cases [48.29/100,000 person-years]), follow-up time and baseline diabetes (44,781 with diabetes [5.3%]). There were 747,198 subjects with valid data regarding liver cancer mortality (5020 liver cancer deaths [44.03/100,000 person-years]), follow-up time and baseline diabetes (43,243 with diabetes [5.8%]). Hazard ratio (HR) (95% confidence interval [95%CI]) of liver cancer diagnosis in those with vs. without baseline diabetes was 1.97 (1.79, 2.16) (p < .0001) after adjusting for baseline age, gender, body mass index, tobacco smoking, alcohol use, and heterogeneity across studies (n = 586,072; events = 4620). Baseline diabetes was associated with increased cumulative incidence of death due to liver cancer (adjusted HR (95%CI) = 1.97 (1.79, 2.18); p < .0001) (n = 595,193; events = 4110). A two-stage meta-analytic approach showed similar results. This paper adds important population-based evidence to current literature regarding the increased incidence and mortality of liver cancer in adults with diabetes. The analysis of data pooled from 20 studies of different Asian countries and the meta-analysis across studies with large number of subjects makes the results robust.

Relationship between urinary potassium excretion, serum potassium levels and cardiac injury in non-dialysis chronic kidney disease: KoreaN cohort study for Outcome in patients With Chronic Kidney Disease (KNOW-CKD).

Although the cardiovascular benefits of an increased urinary potassium excretion have been suggested, little is known about the potential cardiac association of urinary potassium excretion in patients with chronic kidney disease. In addition, whether the cardiac association of urinary potassium excretion was mediated by serum potassium levels has not been studied yet. We reviewed the data of 1633 patients from a large-scale multicentre prospective Korean study (2011-2016). Spot urinary potassium to creatinine ratio was used as a surrogate for urinary potassium excretion. Cardiac injury was defined as a high-sensitivity troponin T ≥ 14 ng/l. OR and 95 % (CI for cardiac injury were calculated using logistic regression analyses. Of 1633 patients, the mean spot urinary potassium to creatinine ratio was 49·5 (sd 22·6) mmol/g Cr and the overall prevalence of cardiac injury was 33·9 %. Although serum potassium levels were not associated with cardiac injury, per 10 mmol/g Cr increase in the spot urinary potassium to creatinine ratio was associated with decreased odds of cardiac injury: OR 0·917 (95 % CI 0·841, 0·998), P = 0·047) in multivariate logistic regression analysis. In mediation analysis, approximately 6·4 % of the relationship between spot urinary potassium to creatinine ratio and cardiac injury was mediated by serum potassium levels, which was not statistically significant (P = 0·368). Higher urinary potassium excretion was associated with lower odds of cardiac injury, which was not mediated by serum potassium levels.

Ethnic-specific associations between body mass index and gastric cancer: a Mendelian randomization study in European and Korean populations.

BACKGROUND: Given the uncertainties surrounding the associations in previous epidemiological studies, we conducted linear and nonlinear Mendelian randomization (MR) studies to evaluate whether body mass index (BMI) associated with gastric cancer (GC) risk in European and Korean. METHODS: Genome-wide association study-summary statistics were used from the Pan-UK Biobank, the Genetic Investigation of Anthropometric Traits consortium, the K-CHIP consortium, and BioBank Japan. BMI-associated single nucleotide polymorphisms (SNPs) were used as instrumental variables (IVs) in MR to identify the association between BMI and GC. Both linear and nonlinear MR analyses were performed. Sensitivity analyses were also conducted for individuals below or above a BMI of 24 kg/m2. RESULTS: The study used 22 and 55 SNPs as IVs for BMI in European and Korean populations, respectively. Genetically predicted BMI was positively associated with GC risk in the European population (Odds ratio per 1 kg/m2 increase; 95% CI = 1.17; 1.01-1.36 using simple median method), but no significant association was observed in the Korean population. However, the nonlinear MR identified a U-shaped association between BMI and GC in the Korean population, with both low and high BMIs associated with increased GC risk. A BMI of 24 kg/m2 presented the lowest risk. Sensitivity analyses did not yield any genome-wide significant SNPs. CONCLUSION: While MR analysis suggests a linear association between BMI and GC in those of European ancestry, nonlinear MR hints at a U-shaped association in Koreans. This suggests the association between BMI and GC risk may vary according to ethnic ancestry.

Family history and gastric cancer incidence and mortality in Asia: a pooled analysis of more than half a million participants.

BACKGROUND: The family history of gastric cancer holds important implications for cancer surveillance and prevention, yet existing evidence predominantly comes from case-control studies. We aimed to investigate the association between family history of gastric cancer and gastric cancer risk overall and by various subtypes in Asians in a prospective study. METHODS: We included 12 prospective cohorts with 550,508 participants in the Asia Cohort Consortium. Cox proportional hazard regression was used to estimate study-specific adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between family history of gastric cancer and gastric cancer incidence and mortality, then pooled using random-effects meta-analyses. Stratified analyses were performed for the anatomical subsites and histological subtypes. RESULTS: During the mean follow-up of 15.6 years, 2258 incident gastric cancers and 5194 gastric cancer deaths occurred. The risk of incident gastric cancer was higher in individuals with a family history of gastric cancer (HR 1.44, 95% CI 1.32-1.58), similarly in males (1.44, 1.31-1.59) and females (1.45, 1.23-1.70). Family history of gastric cancer was associated with both cardia (HR 1.26, 95% CI 1.00-1.60) and non-cardia subsites (1.49, 1.35-1.65), and with intestinal- (1.48, 1.30-1.70) and diffuse-type (1.59, 1.35-1.87) gastric cancer incidence. Positive associations were also found for gastric cancer mortality (HR 1.30, 95% CI 1.19-1.41). CONCLUSIONS: In this largest prospective study to date on family history and gastric cancer, a familial background of gastric cancer increased the risk of gastric cancer in the Asian population. Targeted education, screening, and intervention in these high-risk groups may reduce the burden of gastric cancer.

Risk Factors for Infertility in Korean Women.

BACKGROUND: Female infertility is a crucial problem with significant implications for individuals and society. In this study, we explore risk factors for infertility in Korean women. METHODS: A total of 986 female patients who visited six major infertility clinics in Korea were recruited from April to December 2014. Fertile age-matched controls were selected from two nationwide survey study participants. Conditional logistic regression after age-matching was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) of each risk factor for infertility. RESULTS: Women with a body mass index (BMI) < 18.5 kg/m² had 1.35 times higher odds of infertility (OR, 1.35; 95% CI, 1.03-1.77), while those with a BMI ≥ 25.0 kg/m² had even higher odds (OR, 2.06; 95% CI, 1.61-2.64) compared to women with a normal BMI (18.5 kg/m² ≤ BMI < 25 kg/m²). Ever-smokers exhibited 4.94 times higher odds of infertility compared to never-smokers (95% CI, 3.45-8.85). Concerning alcohol consumption, women who consumed ≥ 7 glasses at a time showed 3.13 times significantly higher odds of infertility than those who consumed ≤ 4 glasses at a time (95% CI, 1.79-5.48). Lastly, women with thyroid disease demonstrated 1.44 times higher odds of infertility compared to women without thyroid disease (95% CI, 1.00-2.08). CONCLUSION: Female infertility in Korea was associated with underweight, obesity, smoking, alcohol consumption, and thyroid disease.

Novel Genetic Variants Associated with Chronic Kidney Disease Progression.

SIGNIFICANCE STATEMENT: eGFR slope has been used as a surrogate outcome for progression of CKD. However, genetic markers associated with eGFR slope among patients with CKD were unknown. We aimed to identify genetic susceptibility loci associated with eGFR slope. A two-phase genome-wide association study identified single nucleotide polymorphisms (SNPs) in TPPP and FAT1-LINC02374 , and 22 of them were used to derive polygenic risk scores that mark the decline of eGFR by disrupting binding of nearby transcription factors. This work is the first to identify the impact of TPPP and FAT1-LINC02374 on CKD progression, providing predictive markers for the decline of eGFR in patients with CKD. BACKGROUND: The incidence of CKD is associated with genetic factors. However, genetic markers associated with the progression of CKD have not been fully elucidated. METHODS: We conducted a genome-wide association study among 1738 patients with CKD, mainly from the KoreaN cohort study for Outcomes in patients With CKD. The outcome was eGFR slope. We performed a replication study for discovered single nucleotide polymorphisms (SNPs) with P <10 -6 in 2498 patients with CKD from the Chronic Renal Insufficiency Cohort study. Several expression quantitative trait loci (eQTL) studies, pathway enrichment analyses, exploration of epigenetic architecture, and predicting disruption of transcription factor (TF) binding sites explored potential biological implications of the loci. We developed and evaluated the effect of polygenic risk scores (PRS) on incident CKD outcomes. RESULTS: SNPs in two novel loci, TPPP and FAT1-LINC02374 , were replicated (rs59402340 in TPPP , Pdiscovery =7.11×10 -7 , PCRIC =8.13×10 -4 , Pmeta =7.23×10 -8 ; rs28629773 in FAT1-LINC02374 , Pdiscovery =6.08×10 -7 , PCRIC =4.33×10 -2 , Pmeta =1.87×10 -7 ). The eQTL studies revealed that the replicated SNPs regulated the expression level of nearby genes associated with kidney function. Furthermore, these SNPs were near gene enhancer regions and predicted to disrupt the binding of TFs. PRS based on the independently significant top 22 SNPs were significantly associated with CKD outcomes. CONCLUSIONS: This study demonstrates that SNP markers in the TPPP and FAT1-LINC02374 loci could be predictive markers for the decline of eGFR in patients with CKD.

Characteristics According to Frailty Status Among Older Korean Patients With Hypertension.

BACKGROUND: As the prevalence of hypertension increases with age and the proportion of the older population is also on the rise, research on the characteristics of older hypertensive patients and the importance of frailty is necessary. This study aimed to identify clinical characteristics of older hypertension in Korea and to investigate these characteristics based on frailty status. METHODS: The HOW to Optimize eLDerly systolic BP (HOWOLD-BP) is a prospective, multicenter, open-label, randomized clinical trial that aims to compare intensive (target systolic blood pressure [SBP] ≤ 130 mmHg) with standard (target SBP ≤ 140 mmHg) treatment to reduce cardiovascular events in older hypertensive Korean patients aged ≥ 65 years. Data were analyzed through a screening assessment of 2,085 patients recruited from 11 university hospitals. Demographic, functional (physical and cognitive), medical history, laboratory data, quality of life, and medication history of antihypertensive drugs were assessed. RESULTS: The mean age was 73.2 years (standard deviation ± 5.60), and 48.0% (n = 1,001) were male. Prevalent conditions included dyslipidemia (66.5%), obesity (body mass index ≥ 25 kg/m², 53.6%), and diabetes (28.9%). Dizziness and orthostatic hypotension were self-reported by 1.6% (n = 33) and 1.2% (n = 24), respectively. The majority of patients were on two antihypertensive drugs (48.4%), while 27.5% (n = 574) and 20.8% (n = 433) were on 1 and 3 antihypertensive medications, respectively. Frail to pre-frail patients were older and also tended to have dependent instrumental activities of daily living, slower gait speed, weaker grip strength, lower quality of life, and lower cognitive function. The frail to pre-frail group reported more dizziness (2.6% vs. 1.2%, P < 0.001) and had concerning clinical factors, including lower glomerular filtration rate, more comorbidities such as diabetes, stroke, and a history of admission. Frail to pre-frail older hypertensive patients used slightly more antihypertensive medications than robust older hypertensive patients (1.95 vs. 2.06, P = 0.003). Pre-frail to frail patients often chose beta-blockers as a third medication over diuretics. CONCLUSION: This study described the general clinical characteristics of older hypertensive patients in Korea. Frail hypertensive patients face challenges in achieving positive clinical outcomes because of multifactorial causes: they are older, have more morbidities, decreased function, lower quality of life and cognitive function, and take more antihypertensive medications. Therefore, it is essential to comprehensively evaluate and monitor disease-related or drug-related adverse events more frequently during regular check-ups, which is necessary for pre-frail to frail older patients with hypertension. TRIAL REGISTRATION: Clinical Research Information Service Identifier: KCT0003787.

Age at menarche by birth cohort: A pooled analysis of half a million women in Asia.

OBJECTIVES: To evaluate changes in the age at menarche in Asian populations. STUDY DESIGN: Retrospective cohort study. METHODS: We included 548,830 women from six countries in Asia. The data were sourced from 20 cohorts participating in the Asia Cohort Consortium (ACC) and two additional cohort studies: Japan Multi-institutional Collaborative Cohorts (J-MICC), and Japan Nurse Health Study (JNHS) with data on age at menarche. Joinpoint regression was used to evaluate changes in age at menarche by birth year and by country. RESULTS: The study includes data from cohorts in six Asian countries namely, China, Iran, Japan, Korea, Malaysia and Singapore. Birth cohorts ranged from 1873 to 1995. The mean age of menarche was 14.0 years with a standard deviation (SD) of 1.4 years, ranged from 12.6 to 15.5 years. Over 100 years age at menarche showed an overall decrease in all six countries. China showed a mixed pattern of decrease, increase, and subsequent decrease from 1926 to 1960. Iran and Malaysia experienced a sharp decline between about 1985 and 1990, with APC values of -4.48 and -1.24, respectively, while Japan, South Korea, and Singapore exhibited a nearly linear decline since the 1980s, notably with an APC of -3.41 in Singapore from 1993 to 1995. CONCLUSIONS: Overall, we observed a declining age at menarche, while the pace of the change differed by country. Additional long-term observation is needed to examine the contributing factors of differences in trend across Asian countries. The study could serve as a tool to strengthen global health campaigns.

Cross-phenotype association analysis of gastric cancer: in-silico functional annotation based on the disease-gene network.

BACKGROUND: A gene or variant has pleiotropic effects, and genetic variant identification across multiple phenotypes can provide a comprehensive understanding of biological pathways shared among different diseases or phenotypes. Discovery of genetic loci associated with multiple diseases can simultaneously support general interventions. Several meta-analyses have shown genetic associations with gastric cancer (GC); however, no study has identified associations with other phenotypes using this approach. METHODS: Here, we applied disease network analysis and gene-based analysis (GBA) to examine genetic variants linked to GC and simultaneously associated with other phenotypes. We conducted a single-nucleotide polymorphism (SNP) level meta-analysis and GBA through a systematic genome-wide association study (GWAS) linked to GC, to integrate published results for the SNP variants and group them into major GC-associated genes. We then performed disease network and expression quantitative trait loci (eQTL) analyses to evaluate cross-phenotype associations and expression levels of GC-related genes. RESULTS: Seven genes (MTX1, GBAP1, MUC1, TRIM46, THBS3, PSCA, and ABO) were associated with GC as well as blood urea nitrogen (BUN), glomerular filtration rate (GFR), and uric acid (UA). In addition, 17 SNPs regulated the expression of genes located on 1q22, 24 SNPs regulated the expression of PSCA on 8q24.3, and rs7849820 regulated the expression of ABO on 9q34.2. Furthermore, rs1057941 and rs2294008 had the highest posterior causal probabilities of being a causal candidate SNP in 1q22, and 8q24.3, respectively. CONCLUSIONS: These findings identified seven GC-associated genes exhibiting a cross-association with GFR, BUN, and UA.

High intakes of iodine among women during pregnancy and the postpartum period has no adverse effect on thyroid function.

PURPOSE: Given the high consumption of seaweed soup by pregnant and lactating Korean women, concerns have been raised about excessive iodine intake. We evaluated the effects of maternal iodine intake on maternal thyroid function and birth outcomes. We also evaluated iodine intake via seaweed soup during late pregnancy and the early postpartum period. METHODS: A total of 349 pregnant women of the Ideal Breast Milk cohort were recruited in late pregnancy, of whom 302 revisited after delivery. Three-day dietary records were assessed at each visit. Blood was collected for thyroid function test. Obstetrical and birth outcomes were obtained. RESULTS: The median dietary iodine intake was 459 µg/day (interquartile range [IQR] 326.5-647.4 µg/day) during pregnancy. Dietary iodine intake by quartile was not significantly associated with maternal thyroid status, or obstetrical or neonatal outcomes. However, the dietary iodine intake in the early postpartum period was 1759 µg/day (IQR 1026.7-2491.1 µg/day) because of a marked increase in seaweed soup consumption. Of all women, 25.8% consumed seaweed soup more than once over the 3 days of dietary records when pregnant, but the figure rose to 93.4% postpartum. Of postpartum women who consumed seaweed soup daily, the median dietary iodine intakes were 1355, 2394, and 3063 µg/day (soup at one, two, and three-or-four meals). CONCLUSIONS: In these iodine-replete pregnant women, dietary iodine intake during pregnancy showed no effect on maternal thyroid function or birth outcomes. However, iodine intake in the early postpartum period was markedly increased by the frequency of seaweed soup consumption.

Polygenic risk scores for prediction of breast cancer risk in Asian populations.

PURPOSE: Non-European populations are under-represented in genetics studies, hindering clinical implementation of breast cancer polygenic risk scores (PRSs). We aimed to develop PRSs using the largest available studies of Asian ancestry and to assess the transferability of PRS across ethnic subgroups. METHODS: The development data set comprised 138,309 women from 17 case-control studies. PRSs were generated using a clumping and thresholding method, lasso penalized regression, an Empirical Bayes approach, a Bayesian polygenic prediction approach, or linear combinations of multiple PRSs. These PRSs were evaluated in 89,898 women from 3 prospective studies (1592 incident cases). RESULTS: The best performing PRS (genome-wide set of single-nucleotide variations [formerly single-nucleotide polymorphism]) had a hazard ratio per unit SD of 1.62 (95% CI = 1.46-1.80) and an area under the receiver operating curve of 0.635 (95% CI = 0.622-0.649). Combined Asian and European PRSs (333 single-nucleotide variations) had a hazard ratio per SD of 1.53 (95% CI = 1.37-1.71) and an area under the receiver operating curve of 0.621 (95% CI = 0.608-0.635). The distribution of the latter PRS was different across ethnic subgroups, confirming the importance of population-specific calibration for valid estimation of breast cancer risk. CONCLUSION: PRSs developed in this study, from association data from multiple ancestries, can enhance risk stratification for women of Asian ancestry.

Association of blood pressure with cardiovascular outcome and mortality: results from the KNOW-CKD study.

BACKGROUND: Optimal blood pressure (BP) control is a major therapeutic strategy to reduce adverse cardiovascular events (CVEs) and mortality in patients with chronic kidney disease (CKD). We studied the association of BP with adverse cardiovascular outcome and all-cause death in patients with CKD. METHODS: Among 2238 participants from the KoreaN cohort study for Outcome in patients With CKD (KNOW-CKD), 2226 patients with baseline BP measurements were enrolled. The main predictor was systolic BP (SBP) categorized by five levels: <110, 110-119, 120-129, 130-139 and ≥140 mmHg. The primary endpoint was a composite outcome of all-cause death or incident CVEs. We primarily used marginal structural models (MSMs) using averaged and the most recent time-updated SBPs. RESULTS: During the follow-up of 10 233.79 person-years (median 4.60 years), the primary composite outcome occurred in 240 (10.8%) participants, with a corresponding incidence rate of 23.5 [95% confidence interval (CI) 20.7-26.6]/1000 patient-years. MSMs with averaged SBP showed a U-shaped relationship with the primary outcome. Compared with time-updated SBP of 110-119 mmHg, hazard ratios (95% CI) for <110, 120-129, 130-139 and ≥140 mmHg were 2.47 (1.48-4.11), 1.29 (0.80-2.08), 2.15 (1.26-3.69) and 2.19 (1.19-4.01), respectively. MSMs with the most recent SBP also showed similar findings. CONCLUSIONS: In Korean patients with CKD, there was a U-shaped association of SBP with the risk of adverse clinical outcomes. Our findings highlight the importance of BP control and suggest a potential hazard of SBP <110 mmHg.

Association of metabolic comorbidity with myocardial infarction in individuals with a family history of cardiovascular disease: a prospective cohort study.

BACKGROUND: The association between metabolic comorbidity and myocardial infarction (MI) among individuals with a family history of cardiovascular disease (CVD) is yet to be elucidated. We aimed to examine the combined effects of metabolic comorbidities, including diabetes mellitus, hypertension, and dyslipidemia, with a family history of CVD in first-degree on the risk of incident MI. METHODS: This cohort study consisted of 81,803 participants aged 40-89 years without a previous history of MI at baseline from the Korean Genome and Epidemiology Study. We performed Cox proportional hazard regression analysis to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for MI and early-onset MI risk associated with metabolic comorbidity in individuals with a family history of CVD. RESULTS: During a median follow-up of 5 years, 1,075 and 479 cases of total and early-onset MI were reported, respectively. According to the disease score, among individuals who had a positive family history of CVD, the HRs for MI were 1.92 (95% CI: 1.47-2.51) in individuals with one disease, 2.75 (95% CI: 2.09-3.61) in those with two diseases, and 3.74 (95% CI: 2.45-5.71) in those with three diseases at baseline compared to individuals without a family history of CVD and metabolic diseases. Similarly, an increase of the disease score among individuals with a positive family history of CVD was associated with an increase in early-onset MI risk. CONCLUSION: Metabolic comorbidity was significantly associated with an increased risk of MI among individuals with a family history of CVD.

Comparison of the Prevalence of Cardiometabolic Disorders and Comorbidities in Korea and the United States: Analysis of the National Health and Nutrition Examination Survey.

BACKGROUND: Comparison of the prevalence of cardiometabolic disorders (CMDs) and comorbidities in Korea and the United States (US) can be an important indicator for forecasting future risk of cardiovascular events in Korea. This study aimed to estimate and compare the prevalence of hypertension, diabetes mellitus (DM), dyslipidemia, obesity, and metabolic syndrome (MetS) in Korea and the US. METHODS: A total of 15,872 individuals from the US National Health and Nutrition Examination Survey (NHANES) 2003-2014 and 26,492 from the Korea NHANES (KNHANES) 2007-2014 were included. Additionally, 164,339 (139,345 from the Health Examinees-Gem Study and 24,994 from the Cardiovascular Disease Association Study) participants enrolled in the Korea Genome and Epidemiology Study were included to investigate the differences of CMDs between urban and rural regions. To estimate the age-standardized prevalence of CMDs in individuals aged 40-69 years, direct standardization using the World Health Organization standard population was performed. RESULTS: The prevalence of CMDs was lower in Korea than the US (hypertension 49.9% vs. 56.8%; DM 13.4% vs. 14.3%; hypercholesterolemia 16.8% vs. 17.8%; obesity 36.2% vs. 38.6%; and MetS 29.4% vs. 36.5%). According to the median survey years, dyslipidemia has become more prevalent in Korea than in the US since 2010. The prevalence of CMDs was greater in rural than that in urban areas in Korea. CONCLUSION: The prevalence of dyslipidemia in Korea exceeded that of the US after 2010, which was associated with increasing burden of cardiovascular events. The present study suggests that further preventive strategies are needed to mitigate the prevalence of CMDs in Korea.