The Relationship between Body Mass Index and Incident Diabetes Mellitus in Chinese Aged Population: A Cohort Study.

OBJECTIVES: Previous studies reported that overweight older adults had a lower mortality after cardiovascular diseases attack, indicating being thinner might not always be better. However, there is an ongoing debate about what is the optimal range of body mass index (BMI) for the aged population. We aimed to evaluate the value of BMI for the prediction of incident diabetes mellitus (DM) in the Chinese elderly population. METHODS: A total number of 6,911 Chinese elderly people (4,110 men and 2,801 women, aged 71 ± 6.0 years) were included in this cohort study. BMI was measured at baseline (Jan 1, 2014, to Dec 31, 2014). All the participants were further classified into six groups: <18.5 kg/m2, 18.5 to <22.5 kg/m2, 22.5 to <25.0 kg/m2, 25.0 to <27.5 kg/m2, 27.5 to <30.0 kg/m2, and ≥30.0 kg/m2. Fasting blood glucose (FBG) and glycated hemoglobin A1c (HbA1c) were annually measured during follow-up (Jan 1, 2015-May 31, 2019). DM was confirmed if either FBG ≥ 7.0 mmol/L or HbA1c ≥ 6.5%. We used the Cox proportional hazard regression model to evaluate the association between BMI and the prediction of incident DM. RESULTS: Comparing individuals with a BMI range of 18.5 to <22.5 kg/m2 (reference), the hazard ratio for incident DM was 2.13 (95% CI: 1.54~2.95), 2.14 (95% CI: 1.53~3.00), 3.17 (95% CI: 2.19~4.59), 3.15 (95% CI: 1.94~5.09), and 3.14 (95% CI: 1.94~5.09) for the group with a BMI range of 22.5 to <25.0 kg/m2, 25.0 to <27.5 kg/m2, 27.5 to <30.0 kg/m2, and ≥30.0 kg/m2 after adjusting for baseline age, sex, blood pressure, lipid profiles, and eGFR (P trend < 0.001), after adjusting for the abovementioned confounders. The association tended to be closer in men and young participants, compared with their counterparts. CONCLUSIONS: High BMI was associated with a high risk of developing DM in the Chinese aged population. Thus, it is optimal for the aged population to maintain their body weight within a reasonable range to prevent chronic diseases.

Effects of low dose pre-irradiation on hepatic damage and genetic material damage caused by cyclophosphamide.

OBJECTIVE: Cyclophosphamide (CTX) can attack tumour cells, but can also damage the other cells and microstructures of an organism at different levels, such as haematopoietic cells, liver cells, peripheral lymphocyte DNA, and genetic materials. Low dose radiation (LDR) can induce general adaptation reaction. In this study, we explore the effects of low dose radiation on hepatic damage and genetic material damage caused by CTX. MATERIALS AND METHODS: Mice were implanted subcutaneously with S180 cells in the left groin (control group excluded). On days 8 and 11, mice of the LDR and LDR+CTX groups were given 75 mGy of whole-body γ-irradiation; whereas mice of the CTX and LDR+CTX groups were injected intraperitoneally with 3.0 mg of CTX. All mice were sacrificed on day 13. DNA damage of the peripheral lymphocytes, alanine aminotransferase (ALT) activity, total protein (TP), albumin (ALB) of the plasma, malonyl-dialdheyde (MDA) content, superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) activity of the hepatic homogenate, and micronucleus frequency (MNF) of polychromatoerythrocytes in the bone marrow were analysed. RESULTS: The control group had the lowest MDA content and the highest SOD and GSH-PX activity, whereas the CTX group had the highest MDA content and the lowest SOD and GSH-PX activity. Compared with the CTX group, the MDA content decreased significantly (p < 0.01) and the SOD and GSH-PX activity increased significantly (p < 0.05) in the LDR+CTX group. TP and ALB in control group were higher than that of the other groups. Compared with the sham-irradiated group, TP and ALB in the LDR group elevated significantly (p < 0.05). The control group had the lightest DNA damage, whereas the CTX group had the severest. DNA damage in LDR+CTX group was much lighter compared with that of the CTX group (p < 0.05). MNF in the CTX group increased significantly compared with the control and the sham-irradiated groups (p < 0.01). Compared with the CTX group, MNF in LDR+CTX group had a tendency of decline, but without statistical significance (p > 0.05). CONCLUSIONS: Pre-chemotherapeutic LDR can induce the activities of anti-oxidative enzymes and promote the elimination of free radicles to alleviate the damaging effects of oxidative stress to hepatic tissue caused by high-dose CTX. At the same time, LDR has no obvious effect on the ALT activity of plasma, but may have protective effect on the protein synthesis function of the liver. High-dose CTX chemotherapy can cause DNA damage of peripheral lymphocytes; however, LDR before chemotherapy may have certain protective effect on DNA damage. Moreover, CTX has potent mutagenic effect; however, LDR may have no protective effect against the genetic toxicity of CTX chemotherapy.

Trends in general and abdominal obesity among Chinese children and adolescents 1993-2009.

OBJECTIVE: This study aimed to examine the secular trends in body mass index (BMI) and waist circumference (WC), and the prevalence of general and abdominal obesity among Chinese children and adolescents from 1993 to 2009. METHODS: Data were obtained from the China health and nutrition survey conducted from 1993 to 2009. 9693 children and adolescents aged 6-17 years were included in this study, with their height, weight and WC measured. General obesity was defined using the BMI cut-offs for overweight recommended by the International Obesity Task Force, and abdominal obesity was assessed when a WC is above the 90th percentile for gender and age. RESULTS: Among the total participants, mean BMI and WC increased significantly over the period 1993-2009: BMI increased from 17.6 to 17.8 kg m(-2) , and WC increased from 61.4 to 63.1 cm (both increases P < 0.001). The prevalence of general obesity and abdominal obesity increased significantly over the period: general obesity (including overweight) rose from 6.1% to 13.1% and abdominal obesity from 4.9% to 11.7% (both increases P < 0.001). WC and abdominal obesity increased at a relatively higher rate than BMI and general obesity. Upward trends in the prevalence of general and abdominal obesity were observed in all subgroups of gender, age and region (all increases P < 0.05), except for abdominal obesity in girls aged 13-17 years (P = 0.102). CONCLUSION: General and abdominal obesity increased significantly over the past 17 years in Chinese children.