The association between serum methylmalonic acid, cobalamin-related biomarkers, and long-term mortality risk in cancer survivors: a prospective cohort study

Association between methylmalonic acid and prevalence of depression in US adults: evidence from NHANES 2011-2014

Background: Depression is a prevalent mental disorder with high morbidity and mortality globally. Methylmalonic acid (MMA) is involved in the pathogenesis of numerous diseases. However, it is unclear whether there is an association between MMA and the prevalence of depression.Methods: This study enrolled 7866 US adults from the 2011-2014 survey of the National Health and Nutrition Examination Survey (NHANES). Individuals were categorized into depression group and non-depression group based on Patient's Health Questionnaire-9 (PHQ-9) score. The association between MMA concentrations and prevalence of depression was analysed by multivariate logistic and linear regression, restricted cubic spline regression, and subgroup analysis. Mediation analysis was used to explore the role of inflammation in the relationship between MMA and depression.Results: MMA concentrations were higher in participants with depression than those without depression. There was a positive and linear relationship of MMA concentrations with PHQ-9 score and depression risk, respectively. Moreover, the association was stable in most subgroups. Furthermore, inflammatory factors were positively correlated to MMA concentrations and prevalence of depression. In addition, white blood cell, neutrophil and alkaline phosphatase (ALP) mediated the relationship between MMA and depression.Conclusion: Our findings revealed that there was a linear and positive correlation between MMA and the prevalence of depression in US adults, which might be mediated by inflammation.

Higher serum vitamin B6 is associated with lower all-cause mortality among cancer survivors in the National Health and Nutrition Examination Survey

Variations in serum concentrations of vitamin B6, vitamin B12, and folate may influence cancer development and progression. However, the association between these 3 serum B vitamins and all-cause mortality among cancer survivors remains unclear. We evaluated the potential associations between serum vitamins B6, B12, and folate and all-cause mortality among cancer survivors. Our hypothesis proposed that higher serum concentrations of vitamin B6, vitamin B12, and folate might be inversely associated with a lower risk of all-cause mortality in this population. Data from the National Health and Nutrition Examination Survey (NHANES) 1999-2018 were used. All-cause mortality was determined by linking participant data to National Death Index records till 31 December 2019. Serum vitamins B6, B12, and folate status were measured. Multivariable Cox regression analyses were applied to investigate the relationship between serum vitamins B6, B12, and folate concentrations and all-cause mortality among cancer survivors. Serum vitamin B6 was inversely associated with all-cause mortality, with a fully-adjusted HR of 0.54 (95%CI: 0.38, 0.78, Ptrend< .001). However, no statistically significant association was observed between serum vitamin B12 as well as serum folate concentration and all-cause mortality among cancer survivors (B12: fully-adjust HR = 0.90, 95%CI: 0.63, 1.27, Ptrend = .771; folate: fully-adjust HR = 0.82, 95%CI: 0.63, 1.08, Ptrend = .269). No statistically significant interaction for age, sex, and BMI was found in stratified analyses. No non-linear relationship was found except for serum folate. These results suggest that higher serum vitamin B6 may be associated with improved survival in cancer survivors.

Prevalence of Functional Cobalamin Deficiency and Relevant Mortality Risk in the General Population: An Unheeded Phenotype Distinct from Cobalamin Deficiency

BACKGROUND

Current guidelines prioritize monitoring and managing cobalamin (Cbl) deficiency but insufficiently address the issue of functional Cbl deficiency (decreased Cbl sensitivity). This study aims to investigate the prevalence burden of functional Cbl deficiency and to examine its prospective association with mortality risk, compared to Cbl deficiency, among United States (US) adults.

METHOD

The cohort study included 22,513 US participants aged ≥20 years from 1999 to 2014 and was followed up through December 31, 2019. Cbl sensitivity was assessed using a combination of binary classifications for Cbl and methylmalonic acid (MMA) levels, with cutoff values set at 400 pg/mL for Cbl and 250 nmol/L for MMA. Functional Cbl deficiency was defined as elevated MMA and Cbl levels. Serum Cbl levels <148 pmol/L (200 pg/mL) were classified as Cbl deficiency.

RESULTS

In this study, approximately 2.1% of US adults had Cbl deficiency, while the age-adjusted prevalence of functional Cbl deficiency was 4.5%, corresponding to an estimated 10 million US adults. Over a median follow-up period of 10.7 years, there were 4636 recorded deaths. Compared to the MMAlowCbllow group (MMA ≤250 nmol/L, Cbl ≤400 pg/mL), the multivariable-adjusted hazard ratios for all-cause, cardiovascular, and cancer-related mortality in the MMAhighCblhigh group were 1.76 (95% confidence interval [CI]: 1.53-2.02, p < 0.001), 2.17 (95% CI: 1.78-2.67, p < 0.001), and 1.38 (95% CI: 0.95-2.00, p = 0.089). In contrast, the mortality risk associated with Cbl deficiency became insignificant after adjusting for similar confounders. While Cbl supplementation or dietary intake above recommended levels might alleviate Cbl deficiency, they do not appear to reduce the prevalence of functional Cbl deficiency or its associated mortality risk.

CONCLUSION

Compared with Cbl deficiency, functional Cbl deficiency is more frequent and is significantly associated with increased mortality risk in the general population.

Decreased cobalamin sensitivity and biological aging acceleration in the general population

BACKGROUND

The evidence on the association between cobalamin (Cbl) and aging or relevant outcomes is limited and controversial. We aimed to investigate the relationships between cobalamin intake- and function-related biomarkers and biological aging.

METHODS

The study encompassed 22,812 participants aged 20 years and older from the National Health and Nutrition Examination Survey. A panel of biomarkers or algorithms was used to assess biological aging, including Klemera-Doubal Age Acceleration (KDMAccel), Phenotypic age acceleration (PhenoAgeAccel), telomere length, α-Klotho, and PhenoAge advancement. Weighted generalized linear regression analysis was used to assess the associations between cobalamin-intake biomarkers (serum cobalamin, cobalamin intake from food, cobalamin supplement use, serum methylmalonic acid [MMA], and homocysteine [Hcy]) and function-related biomarkers (functional cobalamin deficiency and cobalamin insensitivity index).

RESULTS

Among the 22,812 individuals, the weighted mean (SE) age was 48.3 (0.2) years and 48.0% were males. Unexpectedly, serum and dietary cobalamin as well as serum MMA and Hcy levels were positively associated with most indicators of biological aging. Cobalamin sensitivity was assessed by the combination of binary Cbllow/high and MMAlow/high or Hcylow/high (cutoff values: 400 pg/mL for cobalamin, 250 nmol/L for MMA, and 12.1 μmol/l for Hcy) and a newly constructed cobalamin insensitivity index (based on the multiplicative term of serum cobalamin and serum MMA or Hcy). The multivariable-adjusted β (95%CIs) of KDMAccel in the MMAlowCbllow, MMAlowCblhigh, MMAhighCbllow, and MMAhighCblhigh groups were reference, 0.27 (0.03 to 0.51), 0.85 (0.41 to 1.29), and 7.97 years (5.77 to 10.17) respectively, which were consistent for the combination of serum Hcy and cobalamin. Both cobalamin insensitivity indices were robustly associated with biological aging acceleration in a dose-response pattern (each p < 0.001).

CONCLUSIONS

Decreased cobalamin sensitivity but not cobalamin insufficiency might be associated with biological aging acceleration. Further studies would improve understanding of the underlying mechanisms between decreased cobalamin sensitivity and biological aging acceleration.

Joint association of diabetes mellitus and inflammation status with biological ageing acceleration and premature mortality

BACKGROUND

We aimed to investigate the associations of diabetes mellitus (DM) and C-reactive protein (CRP) with biological ageing acceleration and mortality risk.

METHODS

We analyzed data from 41,634 adults with CRP and DM at baseline. Subjects were categorized into high CRP (>3 mg/L) and low CRP (≤3 mg/L) groups. The cross-sectional endpoints of the study were biological ageing indicators Klemera-Doubal method BioAge acceleration (KDMAccel) and Phenotypic age acceleration (PhenoAgeAccel), and the follow-up endpoints were all-cause mortality and cardiovascular mortality.

RESULTS

In adults with high CRP, compared with those without DM, PhenoAgeAccel increased by 1.66 years (95 % CI: 1.38-1.93), and 8.74 years (95 % CI: 8.25-9.22) in adults with prediabetes and DM, respectively (p for interaction <0.001). Using the CRPlow/non-DM group as a reference, adults in the CRPhigh/non-DM, CRPlow/DM, and CRPhigh/DM groups had significantly advanced biological ageing. Compared to adults without DM, low CRP, and no ageing acceleration, the multivariable-adjusted HRs (95%CIs) of all-cause and cardiovascular mortality in those with DM, CRP, and ageing acceleration were 3.22 (2.79-3.72), and 3.57 (2.81-4.54), respectively.

CONCLUSIONS

These findings suggest that the joint presence of low-grade inflammation and DM might be associated with higher odds of biological ageing acceleration and premature mortality.