Sex differences in the associations between prior weight loss and all-cause or cardiovascular mortality in non-elderly individuals with hyperuricemia: a mortality follow-up study

BACKGROUND

Hyperuricemia, a common metabolic condition, is strongly associated with obesity and represents as an independent risk factor for elevated risk of mortality. This observational study aimed to examine the sex-specific associations of prior long-term weight loss (LTWL), defined as a sustained reduction in body weight maintained for at least 12 months, with all-cause and cardiovascular disease (CVD) mortality in non-elderly individuals with hyperuricemia.

METHODS

Non-elderly individuals with hyperuricemia and a historical maximum body mass index ≥ 25 kg/m2 from the 1999-2018 US National Health and Nutrition Examination Survey were included. Sex-specific associations between prior LTWL (< 5%, 5-9.9%, 10-14.9%, and ≥ 15%) with all-cause and CVD mortality were investigated by weighted multivariable Cox proportional hazard regression analysis and stratified analysis.

RESULTS

Among 5,130 participants included, 505 all-cause (147 from CVD) deaths occurred during a median follow-up of 113 months. Compared with the LTWL < 5% reference group, the hazard ratios and 95% confidence intervals for the LTWL 5-9.9%, 10-14.9% and ≥ 15% groups were 1.11 (0.72-1.71), 1.34 (0.79-2.26) and 1.85 (1.14-2.92), respectively, for all-cause mortality (P for trend = 0.02) and 1.83 (0.76-4.43), 2.15 (0.76-6.10), and 3.76 (1.51-9.36), respectively, for CVD mortality (P for trend = 0.003). Significant associations between LTWL with all-cause and CVD mortality were observed exclusively in female, not male participants.

CONCLUSIONS

Prior LTWL ≥ 5% was associated with increased all-cause and CVD mortality in US non-elderly female participants with hyperuricemia. Additional prospective and longitudinal randomized clinical trials are necessary to further examine the current findings.

A systematic review of evidence that environmental contaminant exposure impedes weight loss and glycemic control during calorie-restricted diets in humans

Calorie-restricted diets cause weight loss and can drive type 2 diabetes remission. However, many patients struggle to achieve clinically relevant weight loss, and the reasons are not well understood. Chemical exposure is associated with obesity and type 2 diabetes development, and some evidence from preclinical experiments suggests it can limit the clinical benefits of calorie restriction. We systematically reviewed the evidence for the effects of environmental chemical exposure on mass loss and glycemic control during diet-induced weight management in humans (PROSPERO: CRD42022339993). Of 222 unique citations, only six papers directly examined this question. Only one targeted people with type 2 diabetes. One linked phthalates and parabens, but not bisphenols, with slower fat loss. Two showed per- and polyfluoroalkyl substances were not associated with mass loss, but with faster subsequent mass regain. One linked impaired adiposity improvements with air pollutants. Two papers reported weight loss-induced elevation in plasma organochlorines associated with altered glycemic control. The risk of bias largely arose from the potential for deviation from the intended diet, and statistics and reporting. The role of chemical exposure in impeding the effectiveness of weight management programs needs to be better understood to provide suitable support to people living with obesity and type 2 diabetes.

Blood Levels of Organochlorine Contaminants Mixtures and Cardiovascular Disease

Importance

Cardiovascular toxic effects derived from high exposures to individual organochlorine compounds are well documented. However, there is no evidence on low but continuous exposure to combined organochlorine compounds in the general population.

Objective

To evaluate the association of combined exposure to several organochlorine compounds, including organochlorine pesticides and polychlorinated biphenyls, with incident cardiovascular disease (CVD) in the general population.

Design, Setting, and Participants

This prospective nested case-control study included data from 2 cohorts: the Swedish Mammography Cohort-Clinical (SMC-C) and the Cohort of 60-Year-Olds (60YO), with matched case-control pairs based on age, sex, and sample date. Baseline blood sampling occurred from November 2003 to September 2009 (SMC-C) and from August 1997 to March 1999 (60YO), with follow-up through December 2017 (SMC-C) and December 2014 (60YO). Participants with myocardial infarction or ischemic stroke were matched with controls for composite CVD evaluation. Data were analyzed from September 2020 to May 2023.

Exposures

A total of 25 organochlorine compounds were measured in blood at baseline by gas chromatography-triple quadrupole mass spectrometry. For 7 compounds, more than 75% of the samples were lower than the limit of detection and not included.

Main Outcomes and Measures

Incident cases of primary myocardial infarction and ischemic stroke were ascertained via linkage to the National Patient Register (International Statistical Classification of Diseases and Related Health Problems, Tenth Revision codes I21 and I63). The quantile-based g-computation method was used to estimate the association between the combined exposure to several organochlorine compounds and composite CVD.

Results

Of 1528 included participants, 1024 (67.0%) were female, and the mean (SD) age was 72 (7.0) years in the SMC-C and 61 (0.1) years in the 60YO. The odds ratio of composite CVD was 1.71 (95% CI, 1.11-2.64) per 1-quartile increment of total organochlorine compounds mixture. Organochlorinated pesticides were the largest contributors, and β-hexachlorocyclohexane and transnonachlor had the highest impact. Most of the outcome was not explained by disturbances in the main cardiometabolic risk factors, ie, high body mass index, hypertension, lipid alteration, or diabetes.

Conclusions and Relevance

In this prospective nested case-control study, participants with higher exposures to organochlorines had an increased probability of experiencing a cardiovascular event, the major cause of death worldwide. Measures may be required to reduce these exposures.

Physical exercise and persistent organic pollutants

Exposure to the legacy and emerging persistent organic pollutants (POPs) incessantly has become an important threat to individual health, which is closely related to neurodevelopment, endocrine and cardiovascular homeostasis. Exercise, on the other hand, has been consistently shown to improve physical fitness. Whereas associations between traditional air pollutants, exercise and lung function have been thoroughly reviewed, reviews on associations between persistent organic pollutants and exercise are scarce. Hence, a literature review focused on exercise, exposure to POPs, and health risk assessment was performed for studies published from 2004 to 2022. The purpose of this review is to provide an overview of exposure pathways and levels of POPs during exercise, as well as the impact of exercise on health concerns attributable to the redistribution, metabolism, and excretion of POPs in vivo. Therein lies a broader array of exercise benefits, including insulin sensitizing, mitochondrial DNA repair, lipid metabolism and intestinal microecological balance. Physical exercise is conducive to reduce POPs body burden and resistant to health hazards of POPs generally. Besides, individual lipid metabolism condition is a critical factor in evaluating potential link in exercise, POPs and health effects.

Excretion of Heavy Metals and Glyphosate in Urine and Hair Before and After Long-Term Fasting in Humans

Background: Dietary exposure to environmental pollutants in humans is an important public health concern. While long-term fasting interrupts the dietary exposure to these substances, fat mobilization as an energy source may also release bioaccumulated substances. This was, to our knowledge, only investigated in obese people decades ago. This study explored the effects of 10-days fasting on the excretion of heavy metals and glyphosate.

Methods: Urinary levels of arsenic, chromium, cobalt, lead, nickel, mercury and glyphosate were measured before and after 10 fasting days in 109 healthy subjects. Additionally, hair analysis was done before and ten weeks after fasting in 22 subjects.

Results: Fasting caused a decrease in body weight, and in urinary arsenic (by 72%) and nickel (by 15%) concentrations. A decrease in lead hair concentrations (by 30%) was documented. Urinary mercury levels were unchanged for chromium, cobalt and glyphosate, which were undetectable in most of the subjects. Additionally, fatigue, sleep disorders, headache and hunger were reduced. Body discomfort symptoms diminished four weeks after food reintroduction.

Conclusions: The results of this study provide the first insights into the changes in heavy metal excretion caused by long-term fasting. Further studies focusing on the kinetics of efflux between different compartments of the body are needed.

Clinical Trial Registration:https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00016657, identifier: DRKS00016657.

A gut dysbiotic microbiota-based hypothesis of human-to-human transmission of non-communicable diseases

Non-communicable diseases (NCDs) have replaced communicable diseases as the leading cause of premature death worldwide over the past century. Increasing numbers of studies have reported a link between NCDs and dysbiotic gut microbiota. Some gut microbiota, such as Helicobacter pylori, have been implicated in person-to-person transmission. Based on these reports, we develop a hypothesis regarding dysbiotic microbiota-associated NCDs, and explore how the presence of communicable NCDs could be confirmedexperimentally. We have also reviewed reports on environmental factors, including a high-fat diet, alcohol, smoking, exercise, radiation and air pollution, which have been associated with dysbiotic microbiota, and determined whether any of these parameters were also associated with NCDs. This review discusses the potential mechanism by which dysbiotic microbiota induced by environmental factors are directly or indirectly involved in person-to-person transmission. The hypothetical interplay between the environment, gut microbiota and host can be tested through high-throughput sequencing, animal models, and cell studies, although each of these modalities presents specific challenges. Confirmation of a causative association of dysbiotic microbiota with NCDs would represent a paradigm shift in efforts to prevent and control these diseases, and should stimulate additional studies on the associations among environmental factors, gut microbiota, and NCDs.