Review of 3-year outcomes of a very-low-energy diet-based outpatient obesity treatment programme

Developing a Decision Aid for Clinical Obesity Services in the Real World: the DACOS Nationwide Pilot Study

PURPOSE

The purpose of this study is to develop a decision aid tool using "real-world" data within the Australian health system to predict weight loss after bariatric surgery and non-surgical care.

MATERIALS AND METHODS

We analyzed patient record data (aged 16+years) from initial review between 2015 and 2020 with 6-month (n=219) and 9-/12-month (n=153) follow-ups at eight clinical obesity services. Primary outcome was percentage total weight loss (%TWL) at 6 months and 9/12 months. Predictors were selected by statistical evidence (p<0.20), effect size (±2%), and clinical judgment. Multiple linear regression and bariatric surgery were used to create simple predictive models. Accuracy was measured using percentage of predictions within 5% of the observed value, and sensitivity and specificity for predicting target weight loss of 5% (non-surgical care) and 15% (bariatric surgery).

RESULTS

Observed %TWL with bariatric surgery vs. non-surgical care was 19% vs. 5% at 6 months and 22% vs. 5% at 9/12 months. Predictors at 6 months with intercept (non-surgical care) of 6% include bariatric surgery (+11%), BMI>60 (-3%), depression (-2%), anxiety (-2%), and eating disorder (-2%). Accuracy, sensitivity, and specificity were 58%, 69%, and 56%. Predictors at 9/12 months with intercept of 5% include bariatric surgery (+15%), type 2 diabetes (+5%), eating disorder (+4%), fatty liver (+2%), atrial fibrillation (-4%), osteoarthritis (-3%), sleep/mental disorders (-2-3%), and ≥10 alcohol drinks/week (-2%). Accuracy, sensitivity, and specificity were 55%, 86%, and 53%.

CONCLUSION

Clinicians may use DACOS to discuss potential weight loss predictors with patients after surgery or non-surgical care.

Obesity and malnutrition in children and adults: A clinical review

Background

In the U.S., children and adults are consuming more low-nutrient foods with added sugar and excess fats as compared to healthy, high-quality calories and micronutrients. This diet is increasing the prevalence of malnutrition and nutritional deficiencies, despite high calorie intake. This is a review of the common micronutrient deficiencies, the risk factors for malnutrition, dietary plans, and the health consequences in children and adults with obesity in the U.S.

Methods

This clinical review of literature was performed on the MEDLINE (PubMed) search engine. A total of 1391 articles were identified and after review, a total of 130 were found to be most pertinent.

Discussion

The most common micronutrient deficiencies found in patients with obesity were vitamin A, thiamine (B1), folate (B9), cobalamin (B12), vitamin D, iron, calcium, and magnesium, especially prior and after bariatric surgery. Diets that produced the most weight reduction also further puts these individuals at risk for worsening malnutrition. Malnutrition and micronutrient deficiencies can worsen health outcomes if not properly managed.

Conclusion

Adequate screening and awareness of malnutrition can improve the health outcomes in patients with obesity. Physiologic changes in response to increased adiposity and inadequate intake increase this population's risk of adverse health effects. Malnutrition affects the individual and contributes to worse public health outcomes. The recommendations for screening for malnutrition are not exclusive to individuals undergoing bariatric procedures and can improve the health outcomes of any patient with obesity. However, clearly, improved nutritional status can assist with metabolism and prevent adverse nutritional outcomes post-bariatric surgery. Clinicians should advise on proper nutrition and be aware of diets that worsen deficiencies.

Impact of specialized obesity management services on the reduction in the use of acute hospital services

Severe obesity affects 4% of Australians and is associated with increased use of healthcare services and higher healthcare costs. This study evaluates the effect of attending a public tertiary obesity service on acute hospital use. This record-linkage study included people aged ≥16 years with severe obesity who attended the Nepean Blue Mountains Family Metabolic Health Service (FMHS), New South Wales, Australia between January 2017, and September 2021. Emergency department (ED) presentations and acute hospital admissions and respective costs in the 1-year and 3-years pre-and-post first FMHS attendance were compared, overall and for adequate attendance (≥5 visits). A total of 640 patients (74% female, 50% <45 years) attended the FMHS, totalling 15 303 occasions of service, average 24 per person. There was a 31.0% and 17.6% reduction in acute admissions and ED presentations, respectively, translating into 34.0% and 23.4% decrease in costs. Adequate engagement was associated with a 48% decreased risk of acute admission (odds ratio 0.52; 95% confidence interval 0.29-0.94). Over 3-years, there was a 19.8% and 20.7% reduction in acute hospital admissions and ED presentations, respectively. Findings indicate that tertiary obesity services reduce acute hospital use. Improved access to specialized obesity management may offload hospitals and contribute to acute healthcare cost avoidance.

Intensive management of obesity in people with Prader-Willi syndrome

PURPOSE

Prader-Willi syndrome (PWS) is characterised by childhood-onset hyperphagia and obesity however limited data are available to guide treatment of obesity in this population. We aimed to evaluate the safety, tolerability, and efficacy of intensive medical weight loss interventions (very-low-energy diets [VLED] and/or pharmacotherapy) in individuals with PWS attending a specialist obesity management service.

METHODS

A retrospective audit was undertaken of individuals with PWS attending the Austin Health Weight Control Clinic between January 2010-April 2021. Main outcome measures were weight outcomes, duration of use, and adverse effects.

RESULTS

Data were available for 18 patients, of whom 15 were treated with intensive weight loss interventions. Median (interquartile range, IQR) age at baseline was 20 years (19-32) with median body weight 90 kg (75-118) and BMI 37 kg/m² (30-51). Median weight loss during VLED (n = 7) was 14 kg (1-20 kg) over 60 weeks. Median weight loss with phentermine-topiramate (n = 7) was 17 kg (IQR 9-19 kg) over 56 weeks. Median weight loss with liraglutide 0.6-3 mg (n = 7), prescribed with topiramate in 3 individuals, was 9 kg (2-14 kg) over 96 weeks. Naltrexone-bupropion resulted in weight loss in 2 of 4 individuals. Thirteen individuals achieved ≥10% weight loss but only 5 individuals maintained ≥10% weight loss at last follow-up. Five individuals discontinued pharmacotherapy due to adverse effects.

CONCLUSIONS

VLED and pharmacotherapy can achieve substantial weight loss in some individuals with PWS though non-adherence results in substantial weight regain. Adverse effects were ascribed to phentermine and topiramate, whereas liraglutide was well-tolerated in this population.

Effectiveness of lifestyle interventions for treatment of overweight/obesity among children in China: A systematic review and meta-analysis

BACKGROUND

Pediatric obesity has become a global public health problem. China has the largest population of obese children in the world. It is important to develop effective interventions to control child obesity. This systematic review summarizes proof from randomized controlled trials to assess the efficacy of lifestyle intervention to reduce BMI and metabolic risk factors for overweight/obese Chinese children.

METHODS

We searched studies from five databases (PubMed, MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, and CNKI). Research that meets the following requirements was included: randomized controlled trials, participants are overweight/obese Chinese children aged <18 years old, and the effectiveness of lifestyle interventions is evaluated.

RESULTS

Eight randomized controlled trials were included. A significant difference was found between the intervention group and the control group for the BMI changes (mean difference = -1.49; 95% CI: -2.20 to -0.77; p < 0.001). Subgroup analyses consistently demonstrated that effects of lifestyle interventions on BMI change including multiple-component interventions (mean difference = -2.03 kg/m²; 95% CI: -3.62 to -0.43; p < 0.001) were stronger than those only with physical activities or health education; effects of lifestyle interventions on BMI change were also strengthened if duration of intervention last for more than 1 year (mean difference = -3.03 kg/m²; 95% CI: -4.00 to -2.06; p = 0.01) or with age during 12-18 years old (mean difference = -1.90 kg/m²; 95% CI: -3.37 to -0.43; p < 0.001).

CONCLUSIONS

Lifestyle interventions are effective in reducing BMI in Chinese children with overweight/obesity, and the effectiveness is more profound when the lifestyle intervention includes multiple components, lasts longer than one year, and/or is conducted among teens. These findings provide an important evidence base for developing and implementing potentially effective lifestyle interventions for the treatment of overweight/obesity among Chinese children.

Skin manifestations after bariatric surgery

Background

Skin signs observed in morbid obesity may change as the weight reduces, especially post-bariatric surgery (BaS). Data concerning the skin findings exclusively in post-BaS patients remain limited.

Methods

Seventy post-BaS patients were examined for cutaneous abnormalities. The patients were divided into those with successful weight loss (% excessive body weight loss (EBWL) of at least 50%) and a non-successful group (%EBWL < 50%).

Results

Forty-six patients with successful weight loss demonstrated a significantly lower prevalence of acanthosis nigricans on the neck, axillae and inguinal areas, keratosis pilaris (KP) and pebble fingers. However, a higher prevalence of alopecia was observed. After adjustment with patients’ factors, KP (adjusted odds ratio (aOR) = 0.21, 95%CI 0.06–0.74, p = 0.02) and pebble fingers (aOR = 0.09, 95%CI 0.01–0.89, p = 0.04) remained significantly less likely in patients with successful weight loss. Laboratory results comparing pre- and post-surgery values revealed significant decreases in fasting plasma glucose, hemoglobin A1c, and triglyceride and an increase of high-density lipoproteins in both groups. However, significant decreases of liver aminotransferases (AST and ALT) were observed only in the successful group (p = 0.04, 0.003). Nonetheless, a decrease in vitamin B12 (p = 0.01) was observed in the successful group.

Conclusion

Weight loss after BaS provided an improvement for metabolic profiles. Successful weight reduction resulted in better skin improvement. However, nutritional supplements may be necessary.

Trial registration

Thai Clinical Trials Registry TCTR20171003002. Registered October 3. 2017, retrospectively registered.

Effects on body weight, eating behavior, and quality of life of a low-energy diet combined with behavioral group treatment of persons with class II or III obesity: A 2-year pilot study

Objective

Obesity is associated with reduced health‐related quality of life (HRQoL). Outcomes of nonsurgical weight loss treatment on HRQoL are inconsistent and it is unclear how much weight reduction, or what type of treatment, is required for significant improvements. This study aimed to evaluate the effects of a lifestyle intervention program on weight, eating behaviors, and HRQoL, and to describe participants' experiences of treatment.

Methods

This 2‐year intervention trial in persons with class II or III obesity comprised a 3‐month liquid low‐energy diet (880 kcal/d) followed by a 3‐month reintroduction to regular foods, combined with behavioral group treatment.

Results

Fifty‐five participants (73% women) were included, mean (SD) age 43.2 (12.4) years, and mean body mass index 42.0 (6.0) kg/m². Mean weight loss at 6, 12, and 24 months was 18.9%, 13.7%, and 7.2%, respectively. Short‐ and long‐term effects on eating behavior were favorable. Twelve of 14 HRQoL domains were improved at 6 months, compared to eight domains at 12 months. After 24 months, 2 of 14 domains, physical and psychosocial functioning, were improved. The treatment program was well accepted by the participants.

Conclusions

Substantial weight loss after 6 months was associated with extensive improvements in HRQoL, comprising the physical, psychosocial, and mental domains. Significant weight regain was observed between 6 and 24 months follow‐up. Modest weight loss after 24 months was associated with moderate improvement in physical functioning and large improvement in psychosocial functioning. The effect on psychosocial functioning is most likely related to both weight loss and behavioral treatment.

Emotional eating in patients attending a specialist obesity treatment service

OBJECTIVE

The prevalence of emotional eating (EE) has increased in the general population over past decades. There is limited information on how common EE is among people seeking obesity treatment. We aimed to estimate the proportion of people with EE, and strength of associations between a predefined set of factors and EE in people referred for obesity treatment.

METHODS

Cross-sectional study recruiting 387 adults from a hospital obesity service. "Emotional eating" was defined as Emotional Eating Scale (EES) score ≥25. Strength of associations were estimated by boot-strapped quantile regression analysis. Results are presented as quantile difference (QD) of EES scores at the 25th, 50th or 75th quantile, and 95% confidence intervals (95%CI).

RESULTS

The study population consisted of 71% women, with a median age of 52 years (interquartile range [IQR]: 42, 61), and a median body mass index of 42 kg/m² (IQR: 37, 49). 187 participants were managed with lifestyle modification alone, 103 with the addition of obesity pharmacotherapy, 79 with bariatric surgery, and 18 with both bariatric surgery and medications. EE was reported by an estimated 58% (95%CI: 53, 63) of participants. Factors with the largest and most consistent magnitude of association with EES differences include age, sex, use of glucagon-like peptide-1 (GLP-1) agonists, history of sleeve gastrectomy and recent bariatric surgery.

CONCLUSION

Emotional eating affected more than half of people referred for obesity treatment. Age, sex, use of GLP-1 agonists, history of sleeve gastrectomy and recent bariatric surgery had the strongest associations with EE. These findings allow hypothesis generation about the underlying physiological mechanisms behind emotional eating for investigation in future research.

A predictive model for non-completion of an intensive specialist obesity service in a public hospital: a case-control study

Background

Despite the growing evidence base supporting intensive lifestyle and medical treatments for severe obesity, patient engagement in specialist obesity services is difficult to achieve and poorly understood. To address this knowledge gap, we aimed to develop a model for predicting non-completion of a specialist multidisciplinary service for clinically severe obesity, termed the Metabolic Rehabilitation Programme (MRP).

Method

Using a case-control study design in a public hospital setting, we extracted data from medical records for all eligible patients with a body mass index (BMI) of ≥35 kg/m² with either type 2 diabetes or fatty liver disease referred to the MRP from 2010 through 2015. Non-completion status (case definition) was coded for patients whom started but dropped-out of the MRP within 12 months. Using multivariable logistic regression, we tested the following baseline predictors hypothesised in previous research: age, gender, BMI, waist circumference, residential distance from the clinic, blood pressure, obstructive sleep apnoea (OSA), current continuous positive airway pressure (CPAP) therapy, current depression/anxiety, diabetes status, and medications. We used receiver operating characteristics and area under the curve to test the performance of models.

Results

Out of the 219 eligible patient records, 78 (35.6%) non-completion cases were identified. Significant differences between non-completers versus completers were: age (47.1 versus 54.5 years, p < 0.001); residential distance from the clinic (21.8 versus 17.1 km, p = 0.018); obstructive sleep apnoea (OSA) (42.9% versus 56.7%, p = 0.050) and CPAP therapy (11.7% versus 28.4%, p = 0.005). The probability of non-completion could be independently associated with age, residential distance, and either OSA or CPAP. There was no statistically significant difference in performance between the alternate models (69.5% versus 66.4%, p = 0.57).

Conclusions

Non-completion of intensive specialist obesity management services is most common among younger patients, with fewer complex care needs, and those living further away from the clinic. Clinicians should be aware of these potential risk factors for dropping out early when managing outpatients with severe obesity, whereas policy makers might consider strategies for increasing access to specialist obesity management services.

Determining patient attendance, access to interventions and clinical outcomes in a publicly funded obesity programme: Results from the Canberra Obesity Management Service

Multi-disciplinary specialist services have a crucial role in the management of patients with obesity. As demand for these services increases, so too does the need to monitor individual service performance and compare outcomes across multiple sites. This paper reports on results from the publicly funded Canberra Obesity Management Service. A descriptive observational study was conducted on new patients who attended an initial medical review from July 2016 to June 2017. Baseline characteristics, comorbidities, attendance, service utilization and outcomes were collated until June 2018. Of the 162 patients identified, 64% continued to attend beyond initial medical review. Dietetics was the most commonly accessed allied health service, followed by exercise physiology and psychology. Very low-energy diet was the most commonly trialled intensive intervention, followed by pharmacotherapy and bariatric surgery. Mean baseline weight for those who continued beyond initial medical review was 142.0 kg (SD 26.6 kg), with a mean weight change of -6.2 kg (SD 10.2 kg) and a mean change in percentage body weight of -5% (SD 7%). Clinically significant weight loss was achieved in 36% of these patients, with a further 47% achieving weight stabilization. Mean Depression, Anxiety and Stress Scale scores reduced from 8-6-8 to 7-5-5, and mean Epworth Sleepiness Scale scores decreased from 8/24 to 6/24. Polysomnography referrals were made for 37% of all new patients, 87% of whom were diagnosed with varying degrees of obstructive sleep apnoea. We present these findings in the hope that they may serve as an example for data collection, individual service monitoring and comparison across multiple obesity services.

Standard baseline data collections in obesity management clinics: A Delphi study with recommendations from an expert panel

We aimed to develop an expert consensus on standardizing data collections in specialist obesity management clinics in Australia. A panel of 16 experts participated in a structured consensus-driven Delphi process to reach agreement on a minimum set of baseline patient data collections for consideration in specialist obesity services. The panel included surgeons, clinicians, allied health professionals (dietician, exercise physiologist, psychologist), a bariatric nurse and obesity researchers. We produced a recommended list of core and useful data items that should comprise the baseline patient data set. Consensus was achieved for recommended measures of demographic, anthropometric, biochemical, weight-loss history, medication, medical history and comorbidity data items using a 70% agreement threshold. In this iterative process, there was also consideration of specific data items for patients referred for bariatric surgery. We present the first expert panel consensus on recommendations for a minimum and standard set of baseline patient data collections in obesity management services in Australia. These may be relevant to other countries with similar obesity management service models. Implementation of these recommendations should facilitate data pooling for clinical audits and research collaborations across clinics seeking to improve the quality of specialist obesity care.

A review and critique of published real-world weight management program studies

BACKGROUND

Beyond the essential but somewhat artificial conditions that typify formal clinical studies, real-world evidence (RWE) of weight loss program effectiveness is paramount for an accurate assessment of such programs and refinement of best practices.

OBJECTIVES

To evaluate the current state of RWE studies and publications on weight loss, identify the range of weight loss components being used in RWE programs, and to provide a general overview of the consistency or lack of consistency with regard to measuring and reporting outcomes.

METHODS

A structured search of PubMed was performed to identify relevant English-language publications from 2006 to December 2017 that reported real-world studies of weight loss among adults. Duplicates, non-relevant publications, articles on weight loss surgery, pediatric studies, randomized controlled trials, studies with self-reported weight loss, no objective weight measures, or that failed to include weight loss results were excluded.

RESULTS

This review included 62 RWE publications. Forty-nine studies included dietary intervention, 37 included exercise, 29 included motivational counseling, and 5 contained some patients who had pharmacologic treatment as part of their weight loss regimen. The numbers of participants per study ranged from 10 to more than 3 million. The interventions reported in the publications included diet, exercise, counseling to promote diet and/or exercise, motivational counseling, and pharmacotherapy, and various combinations of these.

CONCLUSIONS

Despite general acceptance that weight loss programs are capable of facilitating successful outcomes, this review revealed substantial inconsistency in the design and reporting of such programs, making it very difficult to draw conclusions about the comparative merits of different real-world weight loss strategies/components. In addition, there was a marked lack of congruence with current weight loss management guidelines, and notably few studies incorporating anti-obesity medications. There clearly is a need for greater rigor and standardization among designing and reporting RWE weight-loss studies.

Willing to go the extra mile: Prospective evaluation of an intensified non-surgical treatment for patients with morbid obesity

BACKGROUND & AIMS

Bariatric surgery has been well established and considered the treatment of choice in morbid obesity. However, some patients refuse surgery because long-term effects have not been fully elucidated, quality of life might change and lifelong supplementation with vitamins and trace elements may be required. Our aim was to exhaust non-surgical treatment modalities and to evaluate such an intensified treatment alternative.

METHODS

A total of 206 patients (mean age = 46 years; BMI = 49 kg/m²) enrolled since 2013 into a non-surgical multimodality obesity treatment program covered by major health insurances were prospectively evaluated over a three year period. The 12-month treatment course comprised 57 h cognitive-behavioral therapy, 53.5 h physical exercise training, and 43.5 h nutritional therapy offered in small groups. Weight loss was induced by a formula-based, very low-calorie diet for 12 weeks in combination with a gastric balloon. The primary outcome was relative weight loss (RWL). Secondary outcome measures were waist-to-hip ratio, blood pressure, antihypertensive drug treatment, anti-diabetic medication, HbA1c, and quality of life.

RESULTS

166 Patients (81%) completed treatment. Mean (±SD) weight loss after 12 months for women and men were 28.8 kg (±14.7) and 33.7 kg (±19.5), respectively, among completers. RWL was 21.9% (±10.0) and excess weight loss (EWL) was 46.9% (±22.2), whereas intention-to-treat analysis revealed a RWL of 20.0% (±10.4) and an EWL of 42.9% (±22.9). Weight loss was accompanied by improved quality of life, lowered HbA1c values, and a significantly reduced need of antihypertensive and diabetes medications over the study period. Three year follow-up data from the first 78 patients (76% follow-up rate) revealed a RWL of 13% (±13.1) and an EWL of 27.2% (±28.8). The majority of patients (51%) maintained a RWL of 10% or more, and 44% had an EWL > 30%.

CONCLUSIONS

In patients with morbid obesity, an intensified non-surgical multimodality treatment program may achieve significant and sustained weight loss accompanied by improvement of disease markers as well as quality of life for at least three years.

Combining biological and psychosocial baseline variables did not improve prediction of outcome of a very-low-energy diet in a clinic referral population

Consistent, strong predictors of obesity treatment outcomes have not been identified. It has been suggested that broadening the range of predictor variables examined may be valuable. We explored methods to predict outcomes of a very-low-energy diet (VLED)-based programme in a clinically comparable setting, using a wide array of pre-intervention biological and psychosocial participant data. A total of 61 women and 39 men (mean ± standard deviation [SD] body mass index: 39.8 ± 7.3 kg/m² ) underwent an 8-week VLED and 12-month follow-up. At baseline, participants underwent a blood test and assessment of psychological, social and behavioural factors previously associated with treatment outcomes. Logistic regression, linear discriminant analysis, decision trees and random forests were used to model outcomes from baseline variables. Of the 100 participants, 88 completed the VLED and 42 attended the Week 60 visit. Overall prediction rates for weight loss of ≥10% at weeks 8 and 60, and attrition at Week 60, using combined data were between 77.8 and 87.6% for logistic regression, and lower for other methods. When logistic regression analyses included only baseline demographic and anthropometric variables, prediction rates were 76.2-86.1%. In this population, considering a wide range of biological and psychosocial data did not improve outcome prediction compared to simply-obtained baseline characteristics.

How common is substantial weight gain after pregnancy?

BACKGROUND

Although population-based studies indicate that on average, women gain 1-2kg between pregnancies, women with obesity often attribute its development to childbearing. There is little contemporary data available regarding how commonly this occurs, particularly in women of different body mass index (BMI) categories. The aim of this study was to examine inter-pregnancy weight changes among women at a tertiary obstetric hospital in Melbourne, Australia.

METHODS

This was a retrospective review of data from the Birthing Outcomes System electronic record of 19,617 women aged 20 years or older, who delivered at least two consecutive singleton infants at ≥37 weeks' gestation at Mercy Hospital for Women between December 1994 and December 2015. A logistic regression model was used to assess the relationship between gain of ≥4kg/m² between pregnancies and maternal BMI category in the first pregnancy, adjusting for covariates of maternal age, inter-pregnancy interval, and socioeconomic status.

RESULTS

Gain of ≥4kg/m² between the first two pregnancies occurred in 7.5% of normal weight women, 10.5% of overweight women, and 13.4% of women with obesity. One in five women who were normal weight in their first pregnancy increased to overweight or obese BMI categories in their second pregnancy.

CONCLUSIONS

Substantial weight gain in relation to pregnancy affects a considerable proportion of women. Since inter-pregnancy weight gain is associated with several complications in the next pregnancy and longer term, avoiding excessive weight gain during and between pregnancies may prevent adverse health consequences in mothers and offspring.

Assessing the evidence for weight loss strategies in people with and without type 2 diabetes

This review will examine topical issues in weight loss and weight maintenance in people with and without diabetes. A high protein, low glycemic index diet would appear to be best for 12-mo weight maintenance in people without type 2 diabetes. This dietary pattern is currently being explored in a large prevention of diabetes intervention. Intermittent energy restriction is useful but no better than daily energy restriction but there needs to be larger and longer term trials performed. There appears to be no evidence that intermittent fasting or intermittent severe energy restriction has a metabolic benefit beyond the weight loss produced and does not spare lean mass compared with daily energy restriction. Meal replacements are useful and can produce weight loss similar to or better than food restriction alone. Very low calorie diets can produce weight loss of 11-16 kg at 12 mo with persistent weight loss of 1-2 kg at 4-6 years with a very wide variation in long term results. Long term medication or meal replacement support can produce more sustained weight loss. In type 2 diabetes very low carbohydrate diets are strongly recommended by some groups but the long term evidence is very limited and no published trial is longer than 12 mo. Although obesity is strongly genetically based the microbiome may play a small role but human evidence is currently very limited.