1.
Assessment of causal association between thyroid function and lipid metabolism: a Mendelian randomization study.
Wang, JJ, Zhuang, ZH, Shao, CL, Yu, CQ, Wang, WY, Zhang, K, Meng, XB, Gao, J, Tian, J, Zheng, JL, et al
Chinese medical journal. 2021;134(9):1064-1069
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Obesity, dyslipidaemia, and metabolic syndrome are major risk factors for cardiovascular disease, however, effect of thyroid dysfunction on dyslipidaemia and cardiovascular disease is largely unknown. This study used mendelian randomisation (MR), where a genetic variant is used as an instrumental variable to detect the causal effects of exposure to disease. This study used two sample MR analyses to find out whether clinical thyroid function measures show a causal relationship with the changes in lipid levels. The results showed a significant association between the elevated thyrotropin (TSH) level and increased total cholesterol. Also, there was a significant correlation between the free triiodothyronine (FT3): free thyroxine (FT4) ratio and total cholesterol and low-density lipoprotein (LDL). Further robust studies are required to confirm the results and investigate the causal effect of thyroid hormone dysregulation and cardiometabolic diseases due to the limitations of this study. However, healthcare professionals can use the results of this study to understand the importance of the pituitary-thyroid-cardiac axis in lipid metabolism and its impact on cardiometabolic health.
Abstract
BACKGROUND Thyroid dysfunction is associated with cardiovascular diseases. However, the role of thyroid function in lipid metabolism remains partly unknown. The present study aimed to investigate the causal association between thyroid function and serum lipid metabolism via a genetic analysis termed Mendelian randomization (MR). METHODS The MR approach uses a genetic variant as the instrumental variable in epidemiological studies to mimic a randomized controlled trial. A two-sample MR was performed to assess the causal association, using summary statistics from the Atrial Fibrillation Genetics Consortium (n = 537,409) and the Global Lipids Genetics Consortium (n = 188,577). The clinical measures of thyroid function include thyrotropin (TSH), free triiodothyronine (FT3) and free thyroxine (FT4) levels, FT3:FT4 ratio and concentration of thyroid peroxidase antibodies (TPOAb). The serum lipid metabolism traits include total cholesterol (TC) and triglycerides, high-density lipoprotein, and low-density lipoprotein (LDL) levels. The MR estimate and MR inverse variance-weighted method were used to assess the association between thyroid function and serum lipid metabolism. RESULTS The results demonstrated that increased TSH levels were significantly associated with higher TC (β = 0.052, P = 0.002) and LDL (β = 0.041, P = 0.018) levels. In addition, the FT3:FT4 ratio was significantly associated with TC (β = 0.240, P = 0.033) and LDL (β = 0.025, P = 0.027) levels. However, no significant differences were observed between genetically predicted FT4 and TPOAb and serum lipids. CONCLUSION Taken together, the results of the present study suggest an association between thyroid function and serum lipid metabolism, highlighting the importance of the pituitary-thyroid-cardiac axis in dyslipidemia susceptibility.
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Effects of Plant-Based Diets on Weight Status: A Systematic Review.
Tran, E, Dale, HF, Jensen, C, Lied, GA
Diabetes, metabolic syndrome and obesity : targets and therapy. 2020;13:3433-3448
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Being overweight or obese is a huge risk factor for many detrimental conditions. It is estimated that around one-third of the world’s population will be overweight or obese by 2025. Hence there is a need to look at dietary strategies in the prevention and treatment of overweight and obesity. Plant-based diets have always existed, however interest in the topic has increased recently and more research is being done on the health-related effects of different plant-based diets. There are many reasons why someone might convert to a plant-based diet, possible health benefits such as weight management are among the most common. The purpose of this review was to evaluate intervention studies assessing the effects of different plant-based diets on body mass index and weight. The results suggest that plant-based diets may improve weight status in some patient groups. It should be noted that only one study out of the 19 included in the review had normal weight, clinically healthy participants. The study populations for the rest were overweight, obese or had type 2 diabetes. Future research should aim to include a representative study population and apply study diets without dietary restrictions.
Abstract
There is an increasing number of people who convert to a plant-based diet. The desire for health benefits, including weight management, is often a contributing factor behind this dietary choice. The purpose of this review was to evaluate intervention studies assessing the effects of different plant-based diets on body mass index and weight. A literature search was conducted in PubMed until December 2019. Twenty-two publications from 19 studies were included. The majority of them were randomized controlled trials comparing a low-fat vegan diet to an omnivore diet in participants with overweight, type 2 diabetes mellitus and/or cardiovascular disease. All studies reported weight reductions, of which seven revealed significant differences, and four revealed non-significant differences between the intervention and the control groups. The results suggest that plant-based diets may improve weight status in some patient groups. Due to restrictions in fat intake in many studies, followed by reduced energy intake, the effects of the different interventions differ depending on the specific plant-based diets investigated. Future research should aim to include a representative study population and apply study diets without dietary restrictions.