Urinary phthalate concentrations and mortality risk: A population-based study.

Phthalates are widely used as plasticizers. Laboratory-based mechanistic and epidemiological studies suggest that phthalates are detrimental to human health. Here, we present prospective analyses on phthalate exposure and all-cause, as well as cause-specific, mortality from the National Health and Nutrition Examination Survey (NHANES), a population-based cohort. Between 1999 and 2018, urinary concentrations of 12 phthalate metabolites were measured by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry in spot urine samples of 10,881 adults aged 40-85 years, of which 2382 died over a median duration of 8.9 years after sample provision. Multivariable Cox regression analyses adjusted for a wide range of lifestyle factors and comorbidities showed that higher concentrations of mono-benzyl phthalate (MBzP) and Mono-n-butyl phthalate (MnBP) were associated with increased mortality. The hazard ratios for participants in the highest quartiles of MBzP and MnBP concentrations were at 1.27 [95% confidence interval: 1.08, 1.49; p linear trend = 0.002] and 1.35 [1.13, 1.62; p linear trend = 0.005). These findings reinforce the need for monitoring of phthalate exposure in relation to health outcomes.

Increased vitamin B6 turnover is associated with greater mortality risk in the general US population: A prospective biomarker study.

BACKGROUND & AIMS: Vitamin B6 status and mortality risk are inversely associated in different patient groups, while prospective studies in the general population are lacking. Here, for the first time, we evaluated the association between biomarkers of vitamin B6 status and mortality risk in a large population-based study. METHODS: The vitamin B6 vitamers pyridoxal-5'-phosphat (PLP) and 4-pyridoxic acid (4-PA) were measured by high-performance liquid chromatography in the National Health and Nutrition Examination Survey (NHANES) between 2005 and 2010. Participants' vital status and causes of death were recorded until December 2015. Multivariable Cox regression analyses were carried out to estimate Hazard Ratios (HRs) and 95% confidence intervals (CIs) of mortality across quintiles of PLP, 4-PA, and the ratio of 4-PA and PLP. RESULTS: Out of 15,304 study participants aged between 20 and 85 years at baseline, 1666 (7.7%) died during a median follow-up time of 7.8 years. An inverse association between PLP and mortality was found in a multivariable model adjusted for socioeconomic and lifestyle factors but became statistically non-significant upon adjustment for routine biomarkers (C-reactive protein, creatinine, albumin, and alkaline phosphatase). There was a significant linear trend for a positive association between 4-PA levels and mortality risk in the fully adjusted regression model, although a comparison of extreme quintiles (quintile 5 vs. quintile 1) did not show a significant difference (HRQ5vs.Q1 (95% CI): 1.19 (0.93, 1.51), plinear trend = 0.02). A positive association between the 4-PA/PLP ratio and all-cause mortality was observed in the multivariable model, with an HRsQ5vs.Q1 of 1.45 (95% CI: 1.14, 1.85; plinear trend<0.0001). There were no significant associations between the biomarkers and cardiovascular or cancer mortality. The association between 4-PA/PLP and mortality risk was heterogeneous across age groups, and only statistically significant among participants older than 65 years at baseline (HRQ5vs.Q1 (95% CI): 1.72 (1.29, 2.29), plinear trend<0.0001). In this group, 4-PA/PLP was also associated with cancer mortality, with an HR Q5vs.Q1 of 2.16 (1.20, 3.90), plinear trend = 0.02). CONCLUSION: Increased vitamin B6 turnover, as indicated by a higher 4-PA/PLP ratio, was associated with all-cause and cancer mortality among the older U.S. general population. Intervention trials are needed to assess whether older individuals with a high 4-PA/PLP ratio would benefit from increased vitamin B6 intake.

Vitamin B6 Status among Vegetarians: Findings from a Population-Based Survey.

Vitamin B6 from plant foods may have lower bioavailability than vitamin B6 from animal foods, but studies on objectively measured vitamin B6 status among vegetarians compared to non-vegetarians are lacking. Thus, the vitamin B6 status among vegetarians, but also pescatarians, and flexitarians, compared to meat-eaters was assessed in the population-based NHANES study (cycles 2007-2008 and 2009-2010). Data on serum pyridoxal-5'-phosphate (PLP) and 4-pyridoxic acid (4-PA) measured by high-performance liquid chromatography (HPLC) as well as dietary intakes from 24-h recalls were available for 8968 adults aged 20-80 years. Geometric mean (±standard error) PLP concentrations were 58.2 ± 6.0, 52.1 ± 3.7, 49.2 ± 4.6 and 51.0 ± 1.1 nmol/L among vegetarians, pescatarians, flexitarians, and meat-eaters. The 4-PA concentrations were 32.7 ± 4.0, 29.0 ± 2.5, 34.8 ± 5.6 and 33.0 ± 0.7, respectively. There were no statistically significant differences in PLP, 4-PA, and their ratio across the groups in multivariable linear regression models. Overall, the use of vitamin B6 supplements was the strongest predictor of the vitamin B6 status, followed by the dietary vitamin B6 intake. Interestingly, several other covariates were significantly associated with vitamin B6 biomarker levels, particularly serum albumin, creatinine and alkaline phosphatase, and should be considered when assessing the vitamin B6 status. In summary, our findings suggest that a vegetarian diet does not pose a risk for vitamin B6 deficiency.