Types of diet, obesity, and incident type 2 diabetes: Findings from the UK Biobank prospective cohort study

Higher docosahexaenoic acid proportions in blood are inversely associated with the prevalence of prediabetes: Evidence from the UK Biobank

Prediabetes and type 2 diabetes mellitus are growing global health concerns, predisposing individuals to various vascular complications. Lifestyle modifications, including dietary interventions, offer promising avenues for prevention and management. Using a multivariable-adjusted model, we analyzed the cross-sectional associations between plasma proportions (% of total fatty acids) of omega-3 polyunsaturated fatty acids (n3 PUFA, including total n3 PUFA, docosahexaenoic acid [DHA], non-DHA n3 PUFA), and glycated hemoglobin A1c (HbA1c) as well as the prevalence of prediabetes in a sample from the UK Biobank cohort. Our hypothesis was that proportions of n3 PUFA, especially DHA, would by inversely associated with the prediabetes prevalence. The sample (n = 92,762; 54.5% females) had an average age of 56 years and was overweight (mean body mass index = 27). The mean plasma DHA proportion in the sample was 2.03% (standard deviation [SD] = 0.67%), non-DHA n3 PUFA was 2.41% (SD = 1.02%) and total n3 PUFA was 4.43% (SD = 1.56%). Prediabetic individuals were identified by blood HbA1c proportions between 5.7% and 6.4% (39-46 mmol/mol) according to American Diabetes Association criteria. Each of the three n3 PUFA biomarkers was inversely associated with HbA1c proportions. In particular, DHA showed the strongest inverse association, with an OR of 0.62 (95% confidence intervals: 0.58, 0.67; P < .001) when comparing quintiles 5 to 1 in a fully adjusted model. These findings suggest a potential protective role of n3 PUFA, particularly DHA, in mitigating the risk of having prediabetes. Further prospective investigations are needed to clarify whether long-chain n3 PUFA could function as modifiable factors for prediabetes.

Association of healthy diet score and adiposity with risk of colorectal cancer: findings from the UK Biobank prospective cohort study

PURPOSE

To explore the joint association of dietary patterns and adiposity with colorectal cancer (CRC), and whether adiposity mediates the relationship between dietary patterns and CRC risk, which could provide deeper insights into the underlying pathogenesis of CRC.

METHODS

The data of 307,023 participants recruited between 2006 and 2010 were extracted from the UK Biobank study. Healthy diet scores were calculated based on self-reported dietary data at baseline, and participants were categorized into three groups, namely, low, intermediate, and high diet score groups. Cox regression models with hazard ratios (HRs) and 95% confidence intervals (CIs) were used to estimate the effects of the healthy diet score on CRC incidence, adjusting for various covariates. Furthermore, the mediation roles of obesity and central obesity between the healthy diet score and CRC risk were assessed using a counterfactual causal analysis based on Cox regression model. Additionally, joint association between dietary patterns and adiposity on CRC risks was assessed on the additive and multiplicative scales.

RESULTS

Over a median 6.2-year follow-up, 3,276 participants developed CRC. After adjusting for sociodemographic and lifestyle factors, a lower risk of CRC incidence was found for participants with intermediate (HR = 0.83, 95% CI: 0.72 to 0.95) and high diet scores (HR = 0.73, 95% CI: 0.62 to 0.87) compared to those with low diet scores. When compared with the low diet score group, obesity accounted for 4.13% and 7.93% of the total CRC effect in the intermediate and high diet score groups, respectively, while central obesity contributed to 3.68% and 10.02% of the total CRC risk in the intermediate and high diet score groups, respectively. The mediating effect of adiposity on CRC risk was significant in men but not in women. Concurrent unhealthy diet and adiposity multiplied CRC risk.

CONCLUSION

Adiposity-mediated effects were limited in the link between dietary patterns and CRC incidence, implying that solely addressing adiposity may not sufficiently reduce CRC risk. Interventions, such as improving dietary quality in people with adiposity or promoting weight control in those with unhealthy eating habits, may provide an effective strategy to reduce CRC risk.

A diet-wide Mendelian randomization analysis: causal effects of dietary habits on type 2 diabetes

Background

Traditional clinical studies have indicated a link between certain food intakes and type 2 diabetes (T2D), but the causal relationships between different dietary habits and T2D remain unknown. Using Mendelian randomization (MR) approaches, we investigated the potential causal association between dietary habits and T2D risk.

Methods

We collected publicly available genome-wide association studies' summary statistics for 18 dietary habits from the UK Biobank and T2D data from the DIAbetes Genetics Replication And Meta-analysis (DIAGRAM) consortium. We applied the inverse variance weighted (IVW) method, supplemented with the MR-Egger method, weighted median method (WMM), simple method, weighted mode, MR-Egger regression, and the MR pleiotropy residual sum and outlier test to determine whether a particular diet was causal for T2D.

Results

Reliable and robust MR estimates demonstrated that poultry intake has a causal effect on a higher risk of T2D (IVW: OR 6.30, 95% CI 3.573-11.11, p = 2.02e - 10; WMM: OR 5.479, 95% CI 0.2758-10.88, p = 1.19e - 06). Conversely, dried fruit intake (IVW: OR 0.380, 95% CI 0.237-0.608, p = 5.57e - 05; WMM: OR 0.450, 95% CI 0.321-0.630, p = 3.33e - 06) and cereal intake (IVW: OR 0.455, 95% CI 0.317-0.653, p = 1.924e - 05; WMM: OR 0.513, 95% CI 0.379-0.694, p = 1.514e - 05) were causally associated with T2D as protective factors. Sensitivity analyses confirmed the reliability and robustness of these findings.

Discussion

Our study established the causal effects of poultry intake, dried fruit intake, and cereal intake on T2D, identifying poultry intake as a risk factor and the other two as protective factors. Further research into potential mechanisms is required to validate these novel findings.

Optimising antidiabetic medication management for type 2 diabetes and renal dysfunction in Can Tho City, Vietnam

Introduction

The research aimed to delineate and investigate the utilisation of antidiabetic drugs in type 2 diabetes patients with kidney failure at a hospital in Can Tho City, Vietnam.

Material and methods

The research analysed the use of antidiabetic drugs at various time points, determined the drug interaction rate, and evaluated the appropriate use of drugs and the relationship with the achievement of target blood glucose and HbA1c levels. A two-tailed Student's t-test was employed to compare continuous variables, an ANOVA test was used to assess multiple values, and an χ2 test was utilised to evaluate categorical variables.

Results

Insulin monotherapy was the predominant regimen for treating type 2 diabetes in patients with impaired kidney function. Metformin was the most prescribed oral medication. Approximately 85.78% of patients received safe and appropriate diabetes treatment. Statistical analysis revealed a significant relationship between achieving target blood glucose and HbA1c after 3 months and factors such as safe drug use and minimal drug interactions (p < 0.05). Patients with chronic kidney disease demonstrated better blood glucose control compared to those with acute kidney disease.

Conclusions

The most common drug used for type 2 diabetes patients with impaired kidney function was insulin monotherapy, with usage increasing with the severity of chronic kidney disease. The chronic kidney disease group exhibited a higher rate of achieving target blood glucose and HbA1c compared to the acute kidney disease group. Rational, safe, and interaction-free drug use significantly contributed to better blood sugar control compared to less prudent medication choices.

Longitudinal changes in diet quality and food intake before and after diabetes awareness in American adults: the Coronary Artery Risk Development in Young Adults (CARDIA) study

INTRODUCTION

Limited longitudinal research is available examining how American adults make dietary changes after learning they have diabetes. We examined the associations between diabetes awareness and changes in dietary quality and food intake in a prospective cohort from the Coronary Artery Risk Development in Young Adults (CARDIA) study.

RESEARCH DESIGN AND METHODS

A nested case-control design was used. In the original CARDIA study, black and white participants were recruited from four US urban areas and partitioned into one control group (no diabetes over 30-year follow-up) and three case groups (early-onset, intermediate-onset, later-onset diabetes groups) based on timing of diagnosis and first awareness of diabetes. Estimated mean A Priori Diet Quality Score (APDQS), and food subgroup intake were examined at three CARDIA examinations (year (Y)0, Y7, and Y20). The mean APDQS with 95% CIs and food intake (servings/day) were compared across the one control group and three case groups using exam-specific and repeated measures linear regression.

RESULTS

Among 4576 participants (mean age: 25±4 years; 55% female; 49% black race), 653 incident cases (14.3%) of diabetes were observed over 30 years. APDQS was lowest at Y0 when the diabetes-free participants were aged 18-30 years (61.5-62.8), but increased over 20 years with advancing age across all groups (64.6-73.3). Lower APDQS in young adulthood was associated with a higher incidence of diabetes later in life. Diabetes awareness was associated with a net increase of 2.95 points in APDQS. The greatest increase of APDQS was when people learned of their diabetes for the first time (an increase of 5.71 in early-onset and 6.64 in intermediate-onset diabetes groups, respectively).

CONCLUSIONS

Advancing age and diabetes awareness were associated with more favorable dietary changes leading to improved diet quality. Optimal diet quality and healthy food intake in young adulthood seem important to prevent diabetes later in life.

The association of a healthy lifestyle index and imaging-based body fat distribution with glycemic status and Type 2 diabetes in the Multi Ethnic Cohort: a cross-sectional analysis

INTRODUCTION

As several behaviors captured by the Lifestyle Risk Factor Index (LSRI) are protective against Type 2 diabetes (T2D) and may affect body fat distribution, we examined its relation with both outcomes.

METHODS

In a subset of the Multiethnic Cohort, participants from five ethnic groups (60-77 years) were assigned LSRI scores (one point each for consuming <1 (women)/<2 (men) alcoholic drinks/day, ≥1.5 physical activity hours/week, not smoking, and adhering to ≥3/7 dietary recommendations). All participants completed an extensive Quantitative Food Frequency Questionnaire to allow estimation of adherence to intake recommendations for fruits, vegetables, refined and whole grains, fish, processed and non-processed meat. Glycemic/T2D status was classified according to self-reports and fasting glucose. We estimated prevalence odds ratios (POR) of LSRI with glycemic/T2D status and DXA- and MRI-based body fat distribution using logistic regression.

RESULTS

Of 1713 participants, 43% had normoglycemia, 30% Pre-T2D, 9% Undiagnosed T2D, and 18% T2D. Overall, 39% scored 0-2, 49% 3, and 12% 4 LSRI points. T2D prevalence was 55% (POR 0.45; 95% confidence intervals 0.27, 0.76) lower for 4 vs. 0-2 LSRI points with weaker associations for abnormal glycemic status. Despite the low adherence to dietary recommendations (22%), this was the only component related to lower T2D prevalence. The inverse LSRI-T2D association was only observed among Latinos and Japanese Americans in ethnic-specific models. Visceral fat measures were higher in T2D patients and attenuated the LSRI-T2D association.

CONCLUSION

These findings support the role of a healthy lifestyle, especially diet, in T2D prevention with differences across ethnicity.

Associations of Diet with Health Outcomes in the UK Biobank: A Systematic Review

The UK Biobank is a cohort study that collects data on diet, lifestyle, biomarkers, and health to examine diet-disease associations. Based on the UK Biobank, we reviewed 36 studies on diet and three health conditions: type 2 diabetes (T2DM), cardiovascular disease (CVD), and cancer. Most studies used one-time dietary data instead of repeated 24 h recalls, which may lead to measurement errors and bias in estimating diet-disease associations. We also found that most studies focused on single food groups or macronutrients, while few studies adopted a dietary pattern approach. Several studies consistently showed that eating more red and processed meat led to a higher risk of lung and colorectal cancer. The results suggest that high adherence to "healthy" dietary patterns (consuming various food types, with at least three servings/day of whole grain, fruits, and vegetables, and meat and processed meat less than twice a week) slightly lowers the risk of T2DM, CVD, and colorectal cancer. Future research should use multi-omics data and machine learning models to account for the complexity and interactions of dietary components and their effects on disease risk.

Mediation Analysis in Medical Research

BACKGROUND

Mediation analysis addresses the question of the mechanisms by which an exposure causes an outcome. This article is intended to convey basic knowledge of statistical mediation analysis.

METHODS

Selected articles and examples are used to explain the principle of mediation analysis.

RESULTS

The goal of mediation analysis is to express an overall exposure effect as a combination of an indirect and a direct effect. For example, it might be of interest whether the increased risk of diabetes (outcome) due to obesity (exposure) is mediated by insulin resistance (indirect effect), and, if so, how much of a direct effect remains. In this example, insulin resistance is a potential mediator of the effect of obesity on the risk of diabetes. In general, for a mediation analysis to be valid, more confounders must be taken into account than in the estimation of the overall effect size. A regression-based approach can be used to ensure the consideration of all relevant confounders in a mediation analysis.

CONCLUSION

By decomposing the overall exposure effect into indirect and direct components, a mediation analysis can reveal not just whether an exposure causes an outcome, but also how. For a mediation analysis to be valid, however, multiple assumptions must be satisfied that cannot easily be checked, potentially compromising such analyses as compared to the estimation of an overall effect.

Novel plant-based meat alternatives: future opportunities and health considerations

Present food systems threaten population and environmental health. Evidence suggests reduced meat and increased plant-based food consumption would align with climate change and health promotion priorities. Accelerating this transition requires greater understanding of determinants of plant-based food choice. A thriving plant-based food industry has emerged to meet consumer demand and support dietary shift towards plant-based eating. 'Traditional' plant-based diets are low-energy density, nutrient dense, low in saturated fat and purportedly associated with health benefits. However, fast-paced contemporary lifestyles continue to fuel growing demand for meat-mimicking plant-based convenience foods which are typically ultra-processed. Processing can improve product safety and palatability and enable fortification and enrichment. However, deleterious health consequences have been associated with ultra-processing, though there is a paucity of equivocal evidence regarding the health value of novel plant-based meat alternatives (PBMAs) and their capacity to replicate the nutritional profile of meat-equivalents. Thus, despite the health halo often associated with plant-based eating, there is a strong rationale to improve consumer literacy of PBMAs. Understanding the impact of extensive processing on health effects may help to justify the use of innovative methods designed to maintain health benefits associated with particular foods and ingredients. Furthering knowledge regarding the nutritional value of novel PBMAs will increase consumer awareness and thus support informed choice. Finally, knowledge of factors influencing engagement of target consumer subgroups with such products may facilitate production of desirable, healthier PBMAs. Such evidence-based food manufacturing practice has the potential to positively influence future individual and planetary health.

Association between walking pace and incident type 2 diabetes by adiposity level: A prospective cohort study from the UK Biobank

AIMS

To investigate the combined association of adiposity and walking pace with incident type 2 diabetes.

METHODS

We undertook a prospective cohort study in 194 304 White-European participants (mean age 56.5 years, 55.9% women). Participants' walking pace was self-reported as brisk, average or slow. Adiposity measures included body mass index (BMI), waist circumference (WC) and body fat percentage (BF%). Associations were investigated using Cox proportional hazard models, with a 2-year landmark analysis. A four-way decomposition analysis was used for mediation and additive interaction.

RESULTS

The median (interquartile range) follow-up was 5.4 (4.8-6.3) years. During the follow-up period, 4564 participants developed type 2 diabetes. Compared to brisk-walking participants with normal BMI, those with obesity who walked briskly were at an approximately 10- to 12-fold higher risk of type 2 diabetes (hazard ratio [HR] 9.64, 95% confidence interval [CI] 7.24-12.84, in women; HR 11.91, 95% CI 8.80-16.12, in men), whereas those with obesity and walked slowly had an approximately 12- to 15-fold higher risk (HR 12.68, 95% CI 9.62-16.71, in women; HR 15.41, 95% CI 11.27-21.06, in men). There was evidence of an additive interaction between WC and BF% and walking pace among women, explaining 17.8% and 47.9% excess risk respectively. Obesity mediated the association in women and men, accounting for 60.1% and 44.9%, respectively.

CONCLUSIONS

Slow walking pace is a risk factor for type 2 diabetes independent of adiposity. Promoting brisk walking as well as weight management might be an effective type 2 diabetes prevention strategy given their synergistic effects.

Exposure to novel brominated and organophosphate flame retardants and associations with type 2 diabetes in East China: A case-control study

The alternative flame retardants, novel brominated flame retardants (NBFRs) and organophosphate flame retardants (OPFRs) are ubiquitous in the environment and biota and may induce endocrine disruption effects. Associations between traditional endocrine-disrupting chemicals and type 2 diabetes have been extensively reported in epidemiological studies. However, the effects of NBFRs and OPFRs in humans have not been reported to date. This paper reports a case-control study of 344 participants aged 25-80 years from Shandong Province, East China, where potential associations between serum NBFR and OPFR concentrations and type 2 diabetes are assessed for the first time. After adjusting for covariates (i.e., age, sex, body mass index, smoking status, alcohol consumption, triglycerides, and total cholesterol), serum concentrations of pentabromotoluene, 2,3-dibromopropyl 2,4,6-tribromophenyl ether, tri-n-propyl phosphate, triphenyl phosphate, and tris (2-ethylhexyl) phosphate were significantly positively associated with type 2 diabetes. In the control group, decabromodiphenyl ethane and triphenyl phosphate were significantly positively associated with fasting plasma glucose, triglycerides, and high-density lipoprotein cholesterol. In the quantile g-computation model, significant positive mixture effect was found between the flame retardants mixtures and high-density lipoprotein cholesterol levels, and decabromodiphenyl ethane contributed the largest positive weights to the mixture effect. Overall, these findings suggest that exposure to NBFRs and OPFRs may promote type 2 diabetes.