Association of blood manganese concentrations with 24-h based brachial and central blood pressure, and pulse-wave velocity.

Potential environmental determinants of BP and hypertension in older adults are far less known than their lifestyle risk factors. Manganese (Mn) is an essential element for life that may induce changes in blood pressure (BP), but the direction of the association is unclear. We aimed to examine the association of blood manganese (bMn) with 24-h-based brachial, central BP (cBP), and pulse-wave velocity (PWV). With this purpose, we analyzed data from 1009 community-living adults aged >65 years without BP medication. bMn was measured using inductively-coupled plasma-mass spectrometry and 24-h BP with validated devices. The association of bMn (median: 6.77 µg/L; IQR: 5.59-8.27) with daytime brachial and central systolic (SBP) and with diastolic BP (DBP) was non-linear, with BP increases up to around the median of Mn and then stabilization or slight rightward decrease. Mean BP differences (95% confidence interval) comparing Mn Q2 to Q5 (vs Q1 quintile) for brachial daytime SBP were 2.56 (0.22; 4.90), 3.59 (1.22; 5.96), 3.14 (0.77; 5.51) and 1.72 (-0.68; 4.11) mmHg, respectively; and 2.22 (0.70, 3.73), 2.55 (1.01, 4.08), 2.45 (0.91; 3.98), and 1.68 (0.13; 3.24), respectively, for DBP. Daytime central-pressures showed a similar dose-response relationship with bMn as daytime brachial-pressures. The association with nighttime BP was linearly positive for brachial BPs, and only increasing for Q5 for cBP. Regarding PWV, a tendency to significant linear increase along bMn levels was observed (p-trend = 0.042). The present findings extend the scarce evidence on the association between Mn and brachial BP to 2 other vascular parameters, suggesting Mn levels as a candidate risk factor for increasing levels of both brachial and cBPs in older adults, yet further research is needed with larger cohort studies in adults at all age ranges.

Cadmium exposure is associated with reduced grip strength in US adults.

BACKGROUND: Muscle strength is a strong predictor of all-cause mortality in the general population. Recent studies have shown an association between environmental pollution and declined grip strength. No previous research has evaluated the specific association between cadmium exposure, a well-known risk factor of several chronic diseases, and muscle strength. METHODS: Cross-sectional study among 4,197 individuals aged ≥40 years, who participated in the National Health and Nutrition Examination Survey (NHANES) 2011-2014, provided data on grip strength, and had either blood or urine cadmium determinations. Grip strength was measured using a Takei digital handgrip dynamometer, and combined grip strength was calculated as the sum of the largest reading from each hand. RESULTS: Median (interquartile range) concentrations of blood (BCd) and creatinine-corrected urine cadmium (Cr-UCd) were 0.32 µg/L (0.20-4.56) and 0.27 µg/g (0.15-0.46), respectively. After adjusting for sociodemographic, anthropometric, health-related behavioral, and clinical risk factors, and serum creatine phosphokinase concentrations, the highest (vs lowest) quartile of BCd was associated with a reduction in combined grip strength of 1.93 kg (95% confidence interval [CI]: -3.51, -0.34), p-trend <0.001. The corresponding values comparing Cr-UCd quartiles 4 vs 1 were -3.24 kg (95% CI: -5.68, -0.79), p-trend <0.001. These results were consistent across socio-demographic and clinical subgroups. CONCLUSIONS: In the US adult population, higher cadmium exposure was associated with decreased grip strength. These results may have important public health implications given the widespread cadmium exposure.

Selenium and impaired physical function in US and Spanish older adults.

BACKGROUND: Selenium (Se) is a trace element with a narrow safety margin. OBJECTIVES: To evaluate the cross-sectional and longitudinal dose-response association between Se exposure and measures of impaired physical function and disability in older adults. DESIGN: NHANES 2011-2014 cross-sectional (US, n = 1733, age ≥60 years) and Seniors-ENRICA-2 2017-2019 cross-sectional and longitudinal (Spain, n = 2548 and 1741, respectively, age ≥65 years) data were analyzed. Whole blood and serum Se levels were measured using inductively coupled plasma-mass spectrometry. Lower-extremity performance was assessed with the Short Physical Performance Battery, and muscle weakness with a dynamometer. Incident mobility and agility limitations, and disability in instrumental activities of daily living (IADL) were ascertained with standardized questionnaires. Analyses were adjusted for relevant confounders, including physical activity. Results across studies were pooled using random-effects meta-analysis. RESULTS: Meta-analyzed odds ratios (95% confidence interval) per log2 increase in whole blood Se were 0.54 (0.32; 0.76) for weakness, 0.59 (0.34; 0.83) for impaired lower-extremity performance, 0.48 (0.31; 0.68) for mobility limitations, 0.71 (0.45; 0.97) for agility limitations, and 0.34 (0.12; 0.56) for disability in at least one IADL. Analyses for serum Se in NHANES showed similar results. Findings suggest the inverse association with grip strength is progressive below 140 µg/L (p-value for non-linear trend in the Seniors-ENRICA-2 study = 0.13), and above 140 µg/L (p-value for non-linear trend in NHANES = 0.11). In the Seniors-ENRICA-2 cohort, with a 2.2 year follow-up period, a doubling in baseline Se levels were associated with a lower incidence of weakness [odds ratio (95% confidence interval): 0.45 (0.22; 0.91)], impaired lower-extremity performance [0.63 (0.32; 1.23)], mobility [0.43 (0.21; 0.91)] and agility [0.38 (0.18; 0.78)] limitations. DISCUSSION: In US and Spanish older adults, Se concentrations were inversely associated with physical function limitations. Further studies are needed to elucidate underlying mechanisms.