Category: Statistics

JAMA. 2024 Jun 4. doi: 10.1001/jama.2024.4166. Online ahead of print.

ABSTRACT

IMPORTANCE: Falls are the most common cause of injury-related morbidity and mortality in older adults.

OBJECTIVE: To systematically review evidence on the effectiveness and harms of fall prevention interventions in community-dwelling older adults.

DATA SOURCES: MEDLINE, Cumulative Index for Nursing and Allied Health Literature, and Cochrane Central Register of Controlled Clinical Trials for relevant English-language literature published between January 1, 2016, and May 8, 2023, with ongoing surveillance through March 22, 2024.

STUDY SELECTION: Randomized clinical trials of interventions to prevent falls in community-dwelling adults 65 years or older.

DATA EXTRACTION AND SYNTHESIS: Critical appraisal and data abstraction by 2 independent reviewers. Random-effects meta-analyses with Knapp-Hartung adjustment.

MAIN OUTCOMES AND MEASURES: Falls, injurious falls, fall-related fractures, hospitalizations or emergency department visits, people with 1 or more falls, people with injurious falls, people with fall-related fractures, and harms.

RESULTS: Eighty-three fair- to good-quality randomized clinical trials (n = 48 839) examined the effectiveness of 6 fall prevention interventions in older adults. This article focuses on the 2 most studied intervention types: multifactorial (28 studies; n = 27 784) and exercise (37 studies; n = 16 117) interventions. Multifactorial interventions were associated with a statistically significant reduction in falls (incidence rate ratio [IRR], 0.84 [95% CI, 0.74-0.95]) but not a statistically significant reduction in individual risk of 1 or more falls (relative risk [RR], 0.96 [95% CI, 0.91-1.02]), injurious falls (IRR, 0.92 [95% CI, 0.84-1.01]), fall-related fractures (IRR, 1.01 [95% CI, 0.81-1.26]), individual risk of injurious falls (RR, 0.92 [95% CI, 0.83-1.02]), or individual risk of fall-related fractures (RR, 0.86 [95% CI, 0.60-1.24]). Exercise interventions were associated with statistically significant reductions in falls (IRR, 0.85 [95% CI, 0.75-0.96]), individual risk of 1 or more falls (RR, 0.92 [95% CI, 0.87-0.98]), and injurious falls (IRR, 0.84 [95% CI, 0.74-0.95]) but not individual risk of injurious falls (RR, 0.90 [95% CI, 0.79-1.02]). Harms associated with multifactorial and exercise interventions were not well reported and were generally rare, minor musculoskeletal symptoms associated with exercise.

CONCLUSIONS AND RELEVANCE: Multifactorial and exercise interventions were associated with reduced falls in multiple good-quality trials. Exercise demonstrated the most consistent statistically significant benefit across multiple fall-related outcomes.

PMID:38833257 | DOI:10.1001/jama.2024.4166

J Am Med Inform Assoc. 2024 Jun 4:ocae125. doi: 10.1093/jamia/ocae125. Online ahead of print.

ABSTRACT

OBJECTIVE: This study experimentally evaluated how well lay individuals could interpret and use 4 types of electronic health record (EHR) patient-facing immunization visualizations.

MATERIALS AND METHODS: Participants (n = 69) completed the study using a secure online survey platform. Participants viewed the same immunization information in 1 of 4 EHR-based immunization visualizations: 2 different patient portals (Epic MyChart and eClinicWorks), a downloadable EHR record, and a clinic-generated electronic letter (eLetter). Participants completed a common task, created a standard vaccine schedule form, and answered questions about their perceived workload, subjective numeracy and health literacy, demographic variables, and familiarity with the task.

RESULTS: The design of the immunization visualization significantly affected both task performance measures (time taken to complete the task and number of correct dates). In particular, those using Epic MyChart took significantly longer to complete the task than those using eLetter or eClinicWorks. Those using Epic MyChart entered fewer correct dates than those using the eLetter or eClinicWorks. There were no systematic statistically significant differences in task performance measures based on the numeracy, health literacy, demographic, and experience-related questions we asked.

DISCUSSION: The 4 immunization visualizations had unique design elements that likely contributed to these performance differences.

CONCLUSION: Based on our findings, we provide practical guidance for the design of immunization visualizations, and future studies. Future research should focus on understanding the contexts of use and design elements that make tables an effective type of health data visualization.

PMID:38833256 | DOI:10.1093/jamia/ocae125

JAMA Netw Open. 2024 Jun 3;7(6):e2413004. doi: 10.1001/jamanetworkopen.2024.13004.

ABSTRACT

IMPORTANCE: It is essential to identify inequitable cancer care for ethnic minority groups, which may allow policy change associated with improved survival and decreased mortality and morbidity.

OBJECTIVE: To investigate ethnic disparities in survival and mortality among New Zealand (NZ) patients with head and neck cancer (HNC) and the association of other variables, including socioeconomic status, tumor stage, and age at diagnosis, with survival rates.

DESIGN, SETTING, AND PARTICIPANTS: This retrospective cohort study was conducted among NZ patients diagnosed with specific HNCs from 2010 to 2020. Anonymized data were obtained from the NZ Cancer Registry, including patients diagnosed from International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) codes C00-C14 and C30-C32. Data were analyzed from July 2020 through January 2024.

MAIN OUTCOMES AND MEASURES: Censored Kaplan-Meier estimates were used to analyze survival distribution. Cox regression models were used to estimate the association of age, tumor stage at diagnosis, and socioeconomic status with survival rates. Age-standardized mortality rates were assessed.

RESULTS: Among 6593 patients with HNCs (4590 males [69.6%]; 4187 patients aged 51-75 years [63.5%]), there were 706 Māori individuals (10.7%) and 5887 individuals with other ethnicity (89.3%), including 4327 NZ European individuals (65.6%; defined as New Zealanders of European descent). Māori individuals had a decreased survival proportion at all years after diagnosis compared with individuals with other ethnicity (eg, 66.1% [95% CI, 62.6%% to 69.8%] vs 71.2% [95% CI, 70.0% to 72.4%] at 2 years). At 1 year after diagnosis, Māori individuals did not have a significantly increased mortality rate compared with 5795 individuals with other ethnicity with data (193 deaths [27.3%] vs 1400 deaths [24.2%]; P = .06), but the rate was significantly increased at 5 years after diagnosis (277 deaths [39.3%] vs 2034 deaths [35.1%]; P = .03); there was greater disparity compared with NZ European individuals (1 year: 969 deaths [22.4%]; P = .003; 5 years: 1441 deaths [33.3%]; P = .002). There were persistent age-adjusted mortality rate disparities: 40.1% (95% CI, -25.9% to 71.2%) for Māori individuals and 18.8% (95% CI, -15.4% to 24.4%) for individuals with other ethnicity. Māori individuals were diagnosed at a mean age of 58.0 years (95% CI, 57.1-59.1 years) vs 64.3 years. (95% CI, 64.0-64.7 years) for individuals with other ethnicity, or 5 to 7 years younger, and died at mean age of 63.5 years (95% CI, 62.0-64.9 years) compared with 72.3 years (95% CI, 71.8-72.9 years) for individuals with other ethnicity, or 7 to 10 years earlier. Māori individuals presented with proportionally more advanced disease (only localized disease, 102 patients [14.5%; 95% CI, 12.0%-17.4%] vs 1413 patients [24.0%; 95% CI, 22.9%-25.1%]; P < .001) and showed an increase in regional lymph nodes (276 patients [39.1%; 95% CI, 35.5%-42.9%] vs 1796 patients [30.5%; 95% CI, 29.3%-31.8%]; P < .001) at diagnosis compared with individuals with other ethnicity. Socioeconomic status was not associated with survival.

CONCLUSIONS AND RELEVANCE: This study found that Māori individuals experienced worse survival outcomes and greater mortality rates from HNC in NZ and presented with more advanced disease at a younger age. These findings suggest the need for further research to alleviate these disparities, highlight the importance of research into minority populations with HNC globally, and may encourage equity research for all cancers.

PMID:38833253 | DOI:10.1001/jamanetworkopen.2024.13004

JAMA Netw Open. 2024 Jun 3;7(6):e2414582. doi: 10.1001/jamanetworkopen.2024.14582.

ABSTRACT

IMPORTANCE: Prostate-specific antigen (PSA) screening for prostate cancer is controversial but may be associated with benefit for certain high-risk groups.

OBJECTIVES: To evaluate associations of county-level PSA screening prevalence with prostate cancer outcomes, as well as variation by sociodemographic and clinical factors.

DESIGN, SETTING, AND PARTICIPANTS: This cohort study used data from cancer registries based in 8 US states on Hispanic, non-Hispanic Black, and non-Hispanic White men aged 40 to 99 years who received a diagnosis of prostate cancer between January 1, 2000, and December 31, 2015. Participants were followed up until death or censored after 10 years or December 31, 2018, whichever end point came first. Data were analyzed between September 2023 and January 2024.

EXPOSURE: County-level PSA screening prevalence was estimated using the Behavior Risk Factor Surveillance System survey data from 2004, 2006, 2008, 2010, and 2012 and weighted by population characteristics.

MAIN OUTCOMES AND MEASURES: Multivariable logistic, Cox proportional hazards regression, and competing risks models were fit to estimate adjusted odds ratios (AOR) and adjusted hazard ratios (AHR) for associations of county-level PSA screening prevalence at diagnosis with advanced stage (regional or distant), as well as all-cause and prostate cancer-specific survival.

RESULTS: Of 814 987 men with prostate cancer, the mean (SD) age was 67.3 (9.8) years, 7.8% were Hispanic, 12.2% were non-Hispanic Black, and 80.0% were non-Hispanic White; 17.0% had advanced disease. There were 247 570 deaths over 5 716 703 person-years of follow-up. Men in the highest compared with lowest quintile of county-level PSA screening prevalence at diagnosis had lower odds of advanced vs localized stage (AOR, 0.86; 95% CI, 0.85-0.88), lower all-cause mortality (AHR, 0.86; 95% CI, 0.85-0.87), and lower prostate cancer-specific mortality (AHR, 0.83; 95% CI, 0.81-0.85). Inverse associations between PSA screening prevalence and advanced cancer were strongest among men of Hispanic ethnicity vs other ethnicities (AOR, 0.82; 95% CI, 0.78-0.87), older vs younger men (aged ≥70 years: AOR, 0.77; 95% CI, 0.75-0.79), and those in the Northeast vs other US Census regions (AOR, 0.81; 95% CI, 0.79-0.84). Inverse associations with all-cause mortality were strongest among men of Hispanic ethnicity vs other ethnicities (AHR, 0.82; 95% CI, 0.78-0.85), younger vs older men (AHR, 0.81; 95% CI, 0.77-0.85), those with advanced vs localized disease (AHR, 0.80; 95% CI, 0.78-0.82), and those in the West vs other US Census regions (AHR, 0.89; 95% CI, 0.87-0.90).

CONCLUSIONS AND RELEVANCE: This population-based cohort study of men with prostate cancer suggests that higher county-level prevalence of PSA screening was associated with lower odds of advanced disease, all-cause mortality, and prostate cancer-specific mortality. Associations varied by age, race and ethnicity, and US Census region.

PMID:38833252 | DOI:10.1001/jamanetworkopen.2024.14582

JAMA Netw Open. 2024 Jun 3;7(6):e2414599. doi: 10.1001/jamanetworkopen.2024.14599.

ABSTRACT

IMPORTANCE: It is uncertain to what extent watchful waiting (WW) in men with nonmetastatic prostate cancer (PCa) and a life expectancy of less than 10 years is associated with adverse consequences.

OBJECTIVE: To report transitions to androgen deprivation therapy (ADT), castration-resistant prostate cancer (CRPC), death from PCa, or death from other causes in men treated with a WW strategy.

DESIGN, SETTING, AND PARTICIPANTS: This nationwide, population-based cohort study included men with nonmetastatic PCa diagnosed since 2007 and registered in the National Prostate Cancer Register of Sweden with WW as the primary treatment strategy and with life expectancy less than 10 years. Life expectancy was calculated based on age, the Charlson Comorbidity Index (CCI), and a drug comorbidity index. Observed state transition models complemented observed data to extend follow-up to more than 20 years. Analyses were performed between 2022 and 2023.

EXPOSURE: Nonmetastatic PCa.

MAIN OUTCOMES AND MEASURES: Transitions to ADT, CRPC, death from PCa, and death from other causes were measured using state transition modeling.

RESULTS: The sample included 5234 men (median [IQR] age at diagnosis, 81 [79-84] years). After 5 years, 954 men with low-risk PCa (66.2%) and 740 with high-risk PCa (36.1%) were still alive and not receiving ADT. At 10 years, the corresponding proportions were 25.5% (n = 367) and 10.4% (n = 213), respectively. After 10 years, 59 men with low-risk PCa (4.1%) and 221 with high-risk PCa (10.8%) had transitioned to CRPC. Ten years after diagnosis, 1330 deaths in the low-risk group (92.3%) and 1724 in the high-risk group (84.1%) were from causes other than PCa.

CONCLUSIONS AND RELEVANCE: These findings suggest that the WW management strategy is appropriate for minimizing adverse consequences of PCa in men with a baseline life expectancy of less than 10 years.

PMID:38833251 | DOI:10.1001/jamanetworkopen.2024.14599

JAMA Netw Open. 2024 Jun 3;7(6):e2414686. doi: 10.1001/jamanetworkopen.2024.14686.

ABSTRACT

IMPORTANCE: Military members and veterans (hereafter, veterans) with posttraumatic stress disorder (PTSD) increasingly seek psychiatric service dogs as a complementary intervention, yet the effectiveness of service dogs is understudied.

OBJECTIVE: To estimate the associations between psychiatric service dog partnership and self-reported and clinician-rated PTSD symptom severity, depression, anxiety, and psychosocial functioning after 3 months of intervention among veterans.

DESIGN, SETTING, AND PARTICIPANTS: This nonrandomized controlled trial used standardized and validated assessment instruments completed by participants and administered by blinded clinicians. Recruitment, eligibility screening, and enrollment were conducted between August 2017 and December 2019. Veterans were recruited using the database of an accredited nonprofit service dog organization with constituents throughout the US. Participants were veterans with a PTSD diagnosis; they were allocated to either the intervention group (n = 81) or control group (n = 75). Outcome assessments were performed at baseline and at the 3-month follow-up. Data analyses were completed in October 2023.

INTERVENTIONS: Participants allocated to the intervention group received a psychiatric service dog for PTSD, whereas those allocated to the control group remained on the waiting list based on the date of application submitted to the service dog organization. Both groups had unrestricted access to usual care.

MAIN OUTCOMES AND MEASURES: The primary outcomes were PTSD symptom severity, depression, and anxiety after 3 months, and the secondary outcomes were psychosocial functioning, such as quality of life and social health. The self-reported PTSD Checklist for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) was used to measure symptom severity, and the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) was used to assess PTSD diagnosis (score range for both instruments: 0-80, with higher scores indicating greater PTSD symptoms).

RESULTS: The 156 participants included in the trial had a mean (SD) age of 37.6 (8.3) years and included 117 males (75%), 17 Black or African American individuals (11%), 30 Hispanic individuals (19%), and 117 White individuals (76%). Compared with the control group, the intervention group had significantly lower PTSD symptom severity based on the PTSD Checklist for DSM-5 mean (SD) score (41.9 [16.9] vs 51.7 [16.1]; difference in means, -11.5 [95% CI, -16.2 to -6.6]; P < .001) and the CAPS-5 mean (SD) score (30.2 [10.2] vs 36.9 [10.2]; difference in means, -7.0 [95% CI, -10.8 to -4.5]; P < .001) at 3 months. The intervention group also had significantly lower depression scores (odds ratio [OR], 0.45 [95% CI, 0.23-0.86]; difference in means, -3.3 [95% CI, -6.8 to -0.6]), anxiety (OR, 0.25 [95% CI, 0.13-0.50]; difference in means, -4.4 [95% CI, -6.9 to -2.1]), and most areas of psychosocial functioning (eg, social isolation: OR, 0.34 [95% CI, 0.18-0.64]).

CONCLUSIONS AND RELEVANCE: This nonrandomized controlled trial found that compared with usual care alone, partnership with a trained psychiatric service dog was associated with lower PTSD symptom severity and higher psychosocial functioning in veterans. Psychiatric service dogs may be an effective complementary intervention for military service-related PTSD.

TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT03245814.

PMID:38833250 | DOI:10.1001/jamanetworkopen.2024.14686

JAMA Netw Open. 2024 Jun 3;7(6):e2414709. doi: 10.1001/jamanetworkopen.2024.14709.

ABSTRACT

IMPORTANCE: Concerns exist about teratogenic and long-term neurodevelopmental outcomes of paternal use of valproate during spermatogenesis.

OBJECTIVE: To evaluate the association between paternal use of valproate during spermatogenesis and offspring risk of congenital malformations and neurodevelopmental disorders.

DESIGN, SETTING, AND PARTICIPANTS: This nationwide cohort study included 1 235 353 singletons born in Denmark between January 1, 1997, and December 31, 2017, identified in the Medical Birth Register; 1336 children had fathers who had filled prescriptions for valproate during spermatogenesis. Congenital malformations were identified in the first year of life and neurodevelopmental disorders were identified from 1 year of age until December 31, 2018. Statistical analysis was performed March 2024.

EXPOSURES: Paternal valproate exposure was defined as fathers who filled 1 or more prescriptions for valproate immediately before or during the time of spermatogenesis (ie, 3 months prior to conception).

MAIN OUTCOMES AND MEASURES: Children with major congenital malformations in the first year of life and with neurodevelopmental disorders before death or end of follow-up were identified in Danish health registers. Log-binomial regression was used to estimate adjusted relative risks (ARRs) of congenital malformations, and Cox proportional hazards regression was used to estimate adjusted hazards ratios (AHRs) of neurodevelopmental disorders, adjusted for relevant confounders.

RESULTS: Among 1 235 353 live births (634 415 boys [51.4%] and 600 938 girls [48.6%]), 1336 children (0.1%) had fathers who filled prescriptions for valproate during spermatogenesis. The median follow-up was 10.1 years (IQR, 5.1-14.8 years) for valproate-exposed children and 10.3 years (IQR, 5.2-15.6 years) for valproate-unexposed children. A total of 43 903 children (3.6%) received a diagnosis of major congenital malformations in the first year of life, and 51 633 children (4.2%) received a diagnosis of neurodevelopmental disorders during follow-up. When comparing the risk among valproate-exposed children with that among unexposed children, the ARR of major congenital malformations was 0.89 (95% CI, 0.67-1.18), the AHR of neurodevelopmental disorders was 1.10 (95% CI, 0.88-1.37), and the AHR of autism spectrum disorder was 0.92 (95% CI, 0.65-1.30). In analyses addressing the robustness of the findings (ie, dose-response analyses, sibling analyses, analyses restricted to children of fathers with epilepsy, analyses that used children with paternal lamotrigine exposure as active comparator, and analyses that used children with paternal exposure to valproate only before spermatogenesis as a negative control exposure), there still was no increased risk of any of the included end points.

CONCLUSIONS AND RELEVANCE: In all analyses based on this large Danish cohort study, results suggest that exposure to valproate during spermatogenesis was not associated with offspring risk of congenital malformations or neurodevelopmental disorders, including autism spectrum disorder.

PMID:38833248 | DOI:10.1001/jamanetworkopen.2024.14709

JAMA Netw Open. 2024 Jun 3;7(6):e2414735. doi: 10.1001/jamanetworkopen.2024.14735.

ABSTRACT

IMPORTANCE: Adolescent sleep problems are prevalent, particularly among racial and ethnic minority groups, and can increase morbidity. Despite the numerous strengths of their racial and ethnic group, urban American Indian and Alaska Native adolescents face significant health disparities but are rarely included in health research. Understanding how sleep problems are associated with health outcomes among American Indian and Alaska Native adolescents may elucidate novel targets for interventions to promote health equity.

OBJECTIVE: To assess whether baseline sleep problems are associated with changes in behavioral and cardiometabolic health outcomes among urban American Indian and Alaska Native adolescents 2 years later.

DESIGN, SETTING, AND PARTICIPANTS: American Indian and Alaska Native adolescents were recruited via flyers and community events for an observational cohort study in California. Baseline assessments were conducted among 142 adolescents from March 1, 2018, to March 31, 2020, and follow-ups were conducted among 114 adolescents from December 1, 2020, to June 30, 2022.

EXPOSURES: Baseline actigraphy-assessed sleep duration and efficiency and self-reported sleep disturbances and social jet lag (absolute value of the difference in sleep midpoint on weekends vs weekdays; indicator of circadian misalignment).

MAIN OUTCOMES AND MEASURES: Main outcome measures included self-reported depression (measured using the Patient Health Questionnaire), anxiety (measured using the Generalized Anxiety Disorder 7-item scale), past year alcohol and cannabis use, body mass index, systolic blood pressure (SBP) and diastolic blood pressure (DBP), waist circumference, and glycosylated hemoglobin (HbA1c). Analyses examined whether baseline sleep was associated with health outcomes at follow-up, controlling for age, sex, and baseline outcome measures.

RESULTS: The baseline sample included 142 urban American Indian and Alaska Native adolescents (mean [SD] age, 14.0 [1.4] years; 84 girls [59%]), 80% of whom (n = 114; mean [SD] age, 14.1 [1.3] years; 71 girls [62%]) completed follow-ups. Linear or logistic regressions showed significant negative associations between shorter sleep duration and depression (β = -1.21 [95% CI, -2.19 to -0.24]), anxiety (β = -0.89 [95% CI, -1.76 to -0.03]), DBP (β = -2.03 [95% CI, -3.79 to -0.28]), and HbA1c level (β = -0.15 [95% CI, -0.26 to -0.04]) and likelihood of alcohol (odds ratio [OR], 0.57 [95% CI, 0.36-0.91]) and cannabis use (full week: OR, 0.59 [95% CI, 0.35-0.99]) at follow-up. Greater social jet lag was associated with significantly higher SBP (β = 0.06 [95% CI, 0.01-0.11]) at follow-up.

CONCLUSIONS AND RELEVANCE: This cohort study found significant associations between poor sleep and adverse changes in health outcomes. Findings highlight the importance of developing culturally responsive interventions that target sleep as a key modifiable risk factor to improve the health of American Indian and Alaska Native adolescents.

PMID:38833247 | DOI:10.1001/jamanetworkopen.2024.14735

Perfusion. 2024 Jun 4:2676591241258048. doi: 10.1177/02676591241258048. Online ahead of print.

ABSTRACT

INTRODUCTION: Antithrombin (AT) is a natural anticoagulant essential to enhancing the unfractionated heparin (UFH) anticoagulant effect. Its supplementation in the management of UFH-based anticoagulation during veno-venous extracorporeal membrane oxygenation (VV ECMO) has a strong pathophysiological rationale.

METHODS: This is a single-center, retrospective cohort study of adult VV ECMO patients with anticoagulation maintained by UFH targeting an activated partial thromboplastin time (aPTT) of 40-50 s and AT activity >80%. We compare anticoagulation management and survival outcomes between AT subpopulations, defined by a threshold AT activity ≥80%. Linear and logistic regression analyses were used to evaluate the variation in AT activity and its association with ICU survival.

RESULTS: In 244 patients enrolled from 2009 to 2022, anticoagulation was maintained by a median heparin dose of 11.4 IU/kg/h [IQR: 8.2-14.7] with a mean aPTT of 46.1 s (±7.3) and AT activity of 88.9% (±17.0). A lower mean aPTT, higher dose of UFH and shorter fraction of time without UFH were associated with higher AT activity (p < .01). Higher AT activity showed a consistent association with ICU survival (for 10% increase of AT, odds ratio for ICU mortality: 0.95; 95% CI 0.93-0.97; p value <.01).

CONCLUSIONS: There is a positive association between AT activity and UFH requirements but no significant difference in the rate of bleeding events. A higher mean AT during VV ECMO was associated with ICU survival. Future studies are needed to differentiate between exogenously supplemented versus endogenous AT effect.

PMID:38833217 | DOI:10.1177/02676591241258048

Environ Monit Assess. 2024 Jun 4;196(7):595. doi: 10.1007/s10661-024-12729-5.

ABSTRACT

Aquatic humic substances (AHS) are defined as an important components of organic matter, being composed as small molecules in a supramolecular structure and can interact with metallic ions, thereby altering the bioavailability of these species. To better understand this behavior, AHS were extracted and characterized from Negro River, located near Manaus city and Carú River, that is situated in Itacoatiara city, an area experiencing increasing anthropogenic actions; both were characterized as blackwater rivers. The AHS were characterized by ¹³C nuclear magnetic ressonance and thermochemolysis GC-MS to obtain structural characteristics. Interaction studies with Cu (II), Al (III), and Fe (III) were investigated using fluorescence spectroscopy applied to parallel factor analysis (PARAFAC) and two-dimensional correlation spectroscopy with Fourier transform infrared spectroscopy (2D-COS FTIR). The AHS from dry season had more aromatic fractions not derived from lignin and had higher content of alkyls moities from microbial sources and vegetal tissues of autochthonous origin, while AHS isolated in the rainy season showed more metals in its molecular architecture, lignin units, and polysacharide structures. The study showed that AHS composition from rainy season were able to interact with Al (III), Fe (III), and Cu (II). Two fluorescent components were identified as responsible for interaction: C1 (blue-shifted) and C2 (red-shifted). C1 showed higher complexation capacities but with lower complexation stability constants (K_ML ranged from 0.3 to 7.9 × 10⁵) than C2 (K_ML ranged from 3.1 to 10.0 × 10⁵). 2D-COS FTIR showed that the COO^– and C-O in phenolic were the most important functional groups for interaction with studied metallic ions.

PMID:38833198 | DOI:10.1007/s10661-024-12729-5