Weight fluctuation, mortality, and cardiovascular disease in adults in 18 years of follow-up: Tehran Lipid and Glucose Study.

PURPOSE: Controversies exist in the effect of body weight loss and fluctuation on cardiovascular disease (CVD) and mortality. This study aims to assess the effect of weight variability on CVD and all-cause and cardiovascular mortality in the Tehran Lipid and Glucose Study (TLGS) cohort. METHOD: Participants aged ≥ 40 year at the baseline period with at least 3 BMI measurements were included in this study. After excluding individuals with cancer, CVD, end-stage renal disease, systemic use of glucocorticoids, pregnancy, and missing covariates at the baseline, a total of 3461 participants were enrolled and followed for 18 years. BMI variability was defined using root mean squared error (RMSE) and average successive variability (ASV). In the RMSE method, BMI variability was calculated using the best-fitting model for BMI trend of each subject. Multivariate Cox proportional hazard models were applied to assess BMI variability's effect on CVD and mortality. RESULTS: Among the 3461 participants in this study, the group with the highest weight variability had an increased risk of death for all-cause (HR 1.65; 95% CI 1.21-2.25), non-cardiovascular (HR 1.77; 95% CI 1.24-2.53), and non-cancer (HR 1.77; 95% CI 1.25-2.50) mortality. However, BMI variability showed to be protective against CVD (HR 0.76; 95% CI 0.6-0.97). These findings were significant in males, non-smokers, participants with age ≤ 60 year, BMI < 30, negative BMI slope, and both diabetic and non-diabetic subjects. CONCLUSION: High BMI variability is associated with increased risk of all-cause, non-CVD, and non-cancer mortality, although protective for the CVD event. Appropriate strategies for body weight maintenance after weight loss could be adopted to avoid weight variability, particularly in non-obese subjects.

Natural history of subclinical hypothyroidism and prognostic factors for the development of overt hypothyroidism: Tehran Thyroid Study (TTS).

OBJECTIVE: The significance of subclinical hypothyroidism (SCH) is largely due to its potential risk for developing overt hypothyroidism (OH). Investigations are still exploring predictive factors contributing to the progression of SCH to OH, particularly in patients with mildly elevated serum thyrotropin (TSH). We aimed to clarify the natural history of SCH and the predictive factors of its progression, based on the grade of SCH severity. METHODS: This study was conducted within the framework of the Tehran Thyroid Study (TTS), in which 5783 individuals aged ≥ 20 years were followed. After applying exclusion criteria, data of 270 SCH subjects remained for the analysis. Thyroid function tests were assessed at baseline and every 3 years. RESULTS: Of 270 participants with SCH, 239 (88.5%) had TSH level between 5.06 and 10 mU/L, and 31 (11.4%) had TSH ≥ 10 mU/L. During a median follow-up of 10 years, 40% had TSH within the reference range, 44% maintained elevated TSH, and 16% had added low T4 to the elevated TSH. The annual incidence rate of progression to OH was 22.3 (16.5-101.9) per 1000 person-years [18 (12.6-25.6) for those with TSH 5.07-9.9 mU/L and 57.8 (22.8-101.9) for patients with TSH ≥ 10 mU/L per 1000 person-years (P = 0.001)]. After adjusting age, sex, body mass index (BMI), thyroid peroxidase antibody (TPOAb), and serum TSH, only TPOAb positivity (HR: 2.31; 95% CI 1.10-4.83, P = 0.026) and baseline TSH level ≥ 10 mU/L (HR: 5.14; 95% CI 2.14-12.3, P < 0.001) remained as predictors for development of OH. In patients with TSH 5.07-9.9 mU/L, TPOAb positivity was associated with an increased risk of OH (HR: 2.41; 95% CI 1.10-5.30, P = 0.027). However, in patients with TSH ≥ 10 mU/L, TPOAb positivity was not a predictor (P = 0.49). CONCLUSION: TPOAb and not TSH are associated with the development of OH in individuals with serum TSH below 10 mU/L, and follow-up at regular intervals is recommended in TPOAb-positive individuals with TSH between 5 and 10 mU/L.

Nanoscale origins of creep in calcium silicate hydrates.

The time-dependent response of structural materials dominates our aging infrastructure's life expectancy and has important resilience implications. For calcium-silicate-hydrates, the glue of cement, nanoscale mechanisms underlying time-dependent phenomena are complex and remain poorly understood. This complexity originates in part from the inherent difficulty in studying nanoscale longtime phenomena in atomistic simulations. Herein, we propose a three-staged incremental stress-marching technique to overcome such limitations. The first stage unravels a stretched exponential relaxation, which is ubiquitous in glassy systems. When fully relaxed, the material behaves viscoelastically upon further loading, which is described by the standard solid model. By progressively increasing the interlayer water, the time-dependent response of calcium-silicate-hydrates exhibits a transition from viscoelastic to logarithmic creep. These findings bridge the gap between atomistic simulations and nanomechanical experimental measurements and pave the way for the design of reduced aging construction materials and other disordered systems such as metallic and oxide glasses.

Prevalence of Metabolic Syndrome in Liver Transplant Recipients in Iran.

BACKGROUND: Metabolic syndrome (MetSx) is common among liver transplant recipients. It contributes to morbidity and mortality. OBJECTIVE: To determine the prevalence of MetSx in patients undergoing liver transplantation (LTx) in Iran. METHODS: 202 liver transplant recipients of both sexes completed this study. Relevant information including age, sex, the underlying disease, systolic and diastolic blood pressure, waist circumference, fasting serum levels of blood sugar (FBS), triglyceride (TG), and HDL-cholesterol were measured. The prevalence of MetSx was evaluated at 1, 3, 6, 9, and 12 months after LTx. RESULTS: The prevalence of MetSx was 36.6% after 1 month that decreased to 28.2% after 12 months of follow-up. The lowest prevalence of MetSx (27.7%) was observed 9 months after LTx. Our data showed a decrease in TG and an increase in HDL-C level and no significant changes in blood pressure, waist circumference and FBS during the study period. CONCLUSION: The prevalence of MetSx after LTx is high when compared to the normal population. It seems that a change in diet after transplantation may affect the prevalence of MetSx.

Diagnosis of a congenitally corrected transposition of the great arteries in a 50-year-old multiparous woman.

Congenitally corrected transposition of the great arteries (cc-TGA) is a rare congenital heart disease. In the literature, few patients with this anomaly have been reported to be asymptomatic until after the fifth decade. We describe a 50-year-old female with five pregnancies and successful deliveries, who was unrecognised until late in her fifth decade.