• Gallstone Disease and the Risk of Type 2 Diabetes.

    9 January 2018

    Gallstone disease (GSD) is related to several diabetes risk factors. The present study was to examine whether GSD was independently associated with type 2 diabetes in the China Kadoorie Biobank study. After excluding participants with prevalent diabetes and prior histories of cancer, heart disease, and stroke at baseline, 189,154 men and 272,059 women aged 30-79 years were eligible for analysis. The baseline prevalence of GSD was 5.7% of the included participants. During 4,138,687 person-years of follow-up (median, 9.1 years), a total of 4,735 men and 7,747 women were documented with incident type 2 diabetes. Compared with participants without GSD at baseline, the multivariate-adjusted hazard ratios (HRs) for type 2 diabetes for those with GSD were 1.09 (95% CI: 0.96-1.24; P = 0.206), 1.21 (95% CI: 1.13-1.30; P < 0.001), and 1.17 (95% CI: 1.10-1.25; P < 0.001) in men, women, and the whole cohort respectively. There was no statistically significant heterogeneity between men and women (P = 0.347 for interaction). The association between GSD and type 2 diabetes was strongest among participants who reported ≥5 years since the first diagnosis and were still on treatment at baseline (HR = 1.48; 95% CI: 1.16-1.88; P = 0.001). The present study highlights the importance of developing a novel prevention strategy to mitigate type 2 diabetes through improvement of gastrointestinal health.

  • Age at natural menopause and risk of diabetes in adult women: Findings from the China Kadoorie Biobank study in the Zhejiang area.

    18 December 2017

    AIMS/INTRODUCTION: There has been considerable professional debate on the association between age at menopause and diabetes risk, while the findings are controversial. The present study explored the association between late menopause and the prevalence of diabetes in the Chinese population. MATERIAL AND METHODS: The data were part of the baseline survey of China Kadoorie Biobank from Zhejiang Province. A total of 17,076 postmenopausal women were included in the present study. Logistic regression models were used to calculate the adjusted odds ratios and their 95% confidence intervals. RESULTS: Of the participating women, 1,288 (7.54%) had type 2 diabetes. In comparison with those with menopause at 46-52 years, women with menopause at a later age (≥53 years) were 1.21-fold (95% confidence interval 1.03-1.43) more likely to have diabetes. CONCLUSIONS: The present findings suggested that later age at menopause was associated with an increased prevalence of diabetes.

  • Effect of total, domain-specific, and intensity-specific physical activity on all-cause and cardiovascular mortality among hypertensive adults in China.

    9 January 2018

    We aimed to prospectively examine the associations of total, domain-specific, and intensity-specific physical activity with all-cause and cardiovascular mortality among Chinese hypertensive adults.We performed a prospective cohort study in 150 391 hypertensive participants aged 30-79 years from the China Kadoorie Biobank study of 512 891 participants recruited from 10 diverse areas across China during 2004-2008. Participants with heart disease, stroke, chronic obstructive pulmonary disease, and cancer at baseline were excluded.During 1069 863 person-years of follow-up (median 7.1 years), a total of 5332 men and 4384 women died. Compared with hypertensive participants in the lowest level of total physical activity, the hazard ratios for all-cause mortality were 0.80 (0.76-0.84), 0.69 (0.65-0.73), and 0.67 (0.62-0.72) for those in quartiles 2-4 (Ptrend < 0.001), respectively. Inverse associations were also observed for cardiovascular mortality. Being active in occupational, domestic, and leisure time were associated with lower risk of all-cause and cardiovascular mortality. However, the adjusted ratio for active commuting was 1.08 (1.02-1.15) for all-cause mortality. High levels of low-intensity, moderate-intensity, and vigorous-intensity physical activity were consistently associated with lower risks of all-cause and cardiovascular mortality.Among Chinese hypertensive adults, a higher level of physical activity reduces all-cause and cardiovascular mortality, independent of intensities of physical activity. Not only leisure-time but also occupational and domestic physical activities were benefited.This is an open access article distributed under the Creative Commons Attribution License 4.0 (CCBY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. http://creativecommons.org/licenses/by/4.0.

  • Correcting the Standard Errors of 2-Stage Residual Inclusion Estimators for Mendelian Randomization Studies.

    9 January 2018

    Mendelian randomization studies use genotypes as instrumental variables to test for and estimate the causal effects of modifiable risk factors on outcomes. Two-stage residual inclusion (TSRI) estimators have been used when researchers are willing to make parametric assumptions. However, researchers are currently reporting uncorrected or heteroscedasticity-robust standard errors for these estimates. We compared several different forms of the standard error for linear and logistic TSRI estimates in simulations and in real-data examples. Among others, we consider standard errors modified from the approach of Newey (1987), Terza (2016), and bootstrapping. In our simulations Newey, Terza, bootstrap, and corrected 2-stage least squares (in the linear case) standard errors gave the best results in terms of coverage and type I error. In the real-data examples, the Newey standard errors were 0.5% and 2% larger than the unadjusted standard errors for the linear and logistic TSRI estimators, respectively. We show that TSRI estimators with modified standard errors have correct type I error under the null. Researchers should report TSRI estimates with modified standard errors instead of reporting unadjusted or heteroscedasticity-robust standard errors.

  • Suicidal risk factors of recurrent major depression in Han Chinese women.

    12 December 2017

    The relationship between suicidality and major depression is complex. Socio- demography, clinical features, comorbidity, clinical symptoms, and stressful life events are important factors influencing suicide in major depression, but these are not well defined. Thus, the aim of the present study was to assess the associations between the above-mentioned factors and suicide ideation, suicide plan, and suicide attempt in 6008 Han Chinese women with recurrent major depression (MD). Patients with any suicidality had significantly more MD symptoms, a significantly greater number of stressful life events, a positive family history of MD, a greater number of episodes, a significant experience of melancholia, and earlier age of onset. Comorbidity with dysthymia, generalized anxiety disorder (GAD), social phobia, and animal phobia was seen in suicidal patients. The present findings indicate that specific factors act to increase the likelihood of suicide in MD. Our results may help improve the clinical assessment of suicide risk in depressed patients, especially for women.

  • A comparison of the clinical characteristics of Chinese patients with recurrent major depressive disorder with and without dysthymia.

    9 January 2018

    BACKGROUND: The relationship between major depressive disorder (MDD) and dysthymia, a form of chronic depression, is complex. The two conditions are highly comorbid and it is unclear whether they are two separate disease entities. We investigated the extent to which patients with dysthymia superimposed on major depression can be distinguished from those with recurrent MDD. METHODS: We examined the clinical features in 1970 Han Chinese women with MDD (DSM-IV) between 30 and 60 years of age across China. Logistic regression was used to determine the association between clinical features of MDD and dysthymia and between dysthymia and disorders comorbid with major depression. RESULTS: The 354 cases with dysthymia had more severe MDD than those without, with more episodes of MDD and greater co-morbidity for anxiety disorders. Patients with dysthymia had higher neuroticism scores and were more likely to have a family history of MDD. They were also more likely to have suffered serious life events. LIMITATIONS: Results were obtained in a clinically ascertained sample of Chinese women and may not generalize to community-acquired samples or to other populations. It is not possible to determine whether the associations represent causal relationships. CONCLUSIONS: The additional diagnosis of dysthymia in Chinese women with recurrent MDD defines a meaningful and potentially important subtype. We conclude that in some circumstances it is possible to distinguish double depression from recurrent MDD.

  • Age at onset of major depressive disorder in Han Chinese women: relationship with clinical features and family history.

    8 December 2017

    BACKGROUND: Individuals with early-onset depression may be a clinically distinct group with particular symptom patterns, illness course, comorbidity and family history. This question has not been previously investigated in a Han Chinese population. METHODS: We examined the clinical features of 1970 Han Chinese women with DSM-IV major depressive disorder (MDD) between 30 and 60 years of age across China. Analysis of linear, logistic and multiple logistic regression models was used to determine the association between age at onset (AAO) with continuous, binary and discrete characteristic clinical features of MDD. RESULTS: Earlier AAO was associated with more suicidal ideation and attempts and higher neuroticism, but fewer sleep, appetite and weight changes. Patients with an earlier AAO were more likely to suffer a chronic course (longer illness duration, more MDD episodes and longer index episode), increased rates of MDD in their parents and a lower likelihood of marriage. They tend to have higher comorbidity with anxiety disorders (general anxiety disorder, social phobia and agoraphobia) and dysthymia. CONCLUSIONS: Early AAO in MDD may be an index of a more severe, highly comorbid and familial disorder. Our findings indicate that the features of MDD in China are similar to those reported elsewhere in the world.

  • Examining the relationship between lifetime stressful life events and the onset of major depression in Chinese women.

    8 December 2017

    BACKGROUND: In European and US studies, patients with major depressive disorder (MDD) report more stressful life events (SLEs) than controls, but this relationship has rarely been studied in Chinese populations. METHODS: Sixteen lifetime SLEs were assessed at interview in two groups of Han Chinese women: 1970 clinically ascertained with recurrent MDD and 2597 matched controls. Diagnostic and other risk factor information was assessed at personal interview. Odds ratios (ORs) were calculated by logistic regression. RESULTS: 60% of controls and 72% of cases reported at least one lifetime SLE. Fourteen of the sixteen SLEs occurred significantly more frequently in those with MDD (median odds ratio of 1.6). The three SLEs most strongly associated with risk for MDD (OR>3.0) preceded the onset of MDD the majority of the time: rape (82%), physical abuse (100%) and serious neglect (99%). LIMITATIONS: Our results may apply to females only. SLEs were rated retrospectively and are subject to biases in recollection. We did not assess contextual information for each life event. CONCLUSIONS: More severe SLEs are more strongly associated with MDD. These results support the involvement of psychosocial adversity in the etiology of MDD in China.

  • The relationship between neuroticism, major depressive disorder and comorbid disorders in Chinese women.

    6 December 2017

    OBJECTIVE: The personality trait of neuroticism is a risk factor for major depressive disorder (MDD), but this relationship has not been demonstrated in clinical samples from Asia. METHODS: We examined a large-scale clinical study of Chinese Han women with recurrent major depression and community-acquired controls. RESULTS: Elevated levels of neuroticism increased the risk for lifetime MDD (with an odds ratio of 1.37 per SD), contributed to the comorbidity of MDD with anxiety disorders, and predicted the onset and severity of MDD. Our findings largely replicate those obtained in clinical populations in Europe and US but differ in two ways: we did not find a relationship between melancholia and neuroticism; we found lower mean scores for neuroticism (3.6 in our community control sample). LIMITATIONS: Our findings do not apply to MDD in community-acquired samples and may be limited to Han Chinese women. It is not possible to determine whether the association between neuroticism and MDD reflects a causal relationship. CONCLUSIONS: Neuroticism acts as a risk factor for MDD in Chinese women, as it does in the West and may particularly predispose to comorbidity with anxiety disorders. Cultural factors may have an important effect on its measurement.