How well are we aging? : capturing the complexity of health trajectories of older adults

Despite its positive nature, population aging represents a public health challenge that could be alleviated by maintaining good health during older age. The aim of this thesis was to evaluate how well people are aging, taking the complexity of their health status into account. All four studies included data from the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K). Study I also gathered data from the Kungsholmen Project (KP). The reference population consisted of the people living in the community or in an institution in Stockholm, Sweden. In the KP, they were aged 75+ in 1987, and in SNAC-K, aged 60+ between 2001 and 2004. Study I. Between 1991 and 2010, both prevalence and incidence of disability remained steady with a tendency towards a gradual decline. In this period, survival increased in functionally independent people but remained constant in disabled people. Our findings suggest that we are living longer and healthier lives, at least in urban-dwelling non-impoverished societies with access to adequate health care and public health assistance. Study II. We used four health indicators to characterize the health status of a population of adults aged 60+ living in Stockholm, Sweden: morbidity, physical impairment, cognitive impairment, and mild and severe disabilities. While multimorbidity and slow gait speed were already prevalent (>60% and >20%) among sexagenarians, both cognitive impairment and mild disability were low until age 84, and severe disability was nearly absent until 90. Study III. The four health measures used in Study II were integrated in a health assessment tool (HAT) for assessing and following health changes in older adults. The HAT score ranges from 0-10 (poor-good health). HAT was reliable over time and accurately predicted adverse health outcomes (ROC area hospitalization: 0.78, 95% CI 0.74–0.81; mortality: 0.85, 95% CI 0.83–0.87). At baseline and follow-ups, at least 90% of participants aged 85 or younger were free of severe disability, and half were functionally independent despite some morbidity. Study IV. A HAT score higher than the age-/sex-specific median was related to completion of the chair-stand test (OR: 2.6, 95% CI 2.1–3.3), better balance and grip test results (interaction OR: 1.2, 95% CI 1.1–1.3), and good self-rated health (OR: 2.2, 95% CI 1.8–2.7). HAT predicted social and medical care use better than did disability (p<0.001) and morbidity (HAT better for hospital admission, formal care, and informal care; p<0.001). HAT score can be computed with a flowchart, and the percentile curves help estimate individual health status. Conclusions. The health status of this urban Swedish population was fairly good. Time trends in disability remained stable over 20 years (1991-2010), and at the same time, the increase in life expectancy during recent years appeared to be driven by the longer lives of functionally independent people. Studying the health status of older people using multiple indicators of health, we found that age 80-85 is a transitional period when major health changes take place, often following the co-occurrence of more than one negative health event. HAT, composed of relatively few items, may help assess and identify deviations from expected health trajectories at the individual level and determine medical, rehabilitation, or social care needs at the population level. Determination of individual-level deviations can be facilitated by creating reference health curves similar to the growth charts used by pediatricians. HAT is a reliable and valid health measure and is a good candidate for use in developing such geriatric health charts

Structural health monitoring apparatus and methodology

Disclosed is an apparatus and methodology for structural health monitoring (SHM) in which smart devices interrogate structural components to predict failure, expedite needed repairs, and thus increase the useful life of those components. Piezoelectric wafer active sensors (PWAS) are applied to or integrated with structural components and various data collected there from provide the ability to detect and locate cracking, corrosion, and disbanding through use of pitch-catch, pulse-echo, electro/mechanical impedance, and phased array technology. Stand alone hardware and an associated software program are provided that allow selection of multiple types of SHM investigations as well as multiple types of data analysis to perform a wholesome investigation of a structure

personality and survival in older age the role of lifestyle behaviors and health status

Objective We intended to assess the relationship between personality and survival in an older population and to explore the role of lifestyle behaviors and health status as potential mediators. Design Population-based cohort study. Setting Swedish National Study of Aging and Care in Kungsholmen, Sweden. Participants 2,298 adults aged 60 or more years, without dementia or depression, followed for 11 years. Measurements Personality (extraversion, neuroticism, and openness) was assessed with a shortened version of the NEO-Five Factor Inventory. We tested whether personality affected mortality and examined the potential mediating effect of health status (body mass index, number of chronic diseases, impairment in instrumental activities of daily living, and C-reactive protein) and lifestyle behaviors (leisure activities, social network, smoking, and alcohol consumption). Results Over 11 years of follow-up, higher levels of extraversion were associated with a 14% reduction in mortality. Examination of different combinations of personality traits showed that independent of levels of neuroticism and openness, high extraversion were associated with up to 65% lower mortality. Decomposing the effect of extraversion on mortality, we found that the majority (44%) of the beneficial effect was mediated by healthy lifestyle behaviors. Health status accounted for 5% of the association. Conclusions Extroverted people, who are characterized by higher optimism and high self-efficacy, are prone to healthier behaviors and better health, which may result in longer survival. These results highlight the importance of a healthy lifestyle in survival

Association between metformin use and risk of esophageal squamous cell carcinoma in a population-based cohort study

Objectives: Esophageal cancer is a highly fatal malignant neoplasm, with two etiologically different histological types. A large prospective study is expected to elucidate the specific risk of the 90% subtype of esophageal cancer, esophageal squamous cell carcinoma, with metformin therapy. This study aims to determine the association between metformin use and incident esophageal squamous cell carcinoma risk. Methods: This was a nationwide population-based prospective cohort study conducted in Sweden in 2005-2015. Among 8.4 million participants identified in the cohort, 411,603 (5%) were metformin users. The users were compared with 10 times as many frequency-matched non-users of metformin (n=4,116,030) by age and sex. Metformin use was treated as a time-varying variate and multivariable cause-specific proportional hazards model was used to calculate hazard ratios (HR) with 95% confidence intervals (CI) for esophageal squamous cell carcinoma, adjusted for age, sex, calendar year, residence area, tobacco smoking, alcohol overconsumption, and use of non-steroidal anti-inflammatory drugs or statins. Results: The incidence rates of esophageal squamous cell carcinoma were 3.5 per 100,000 person-years among the metformin users and 5.3 per 100,000 person-years in the non-users. Metformin users overall were at a decreased risk of esophageal squamous cell carcinoma compared with non-users (HR 0.68, 95% CI 0.54-0.85). The decrease in risk was more pronounced in new metformin users (HR 0.44, 95% CI 0.28-0.64) and participants aged 60-69 years (HR 0.45, 95% CI 0.31-0.66). Conclusions: Metformin use decreases the risk of developing esophageal squamous cell carcinoma.Swedish Research CouncilSwedish Cancer SocietyUnited European Research PrizeManuscrip

Incidence and Mortality in Upper Gastrointestinal Cancer After Negative Endoscopy for Gastroesophageal Reflux Disease

BACKGROUND AND AIMS: Gastroesophageal reflux disease (GERD) is associated with an increased risk of cancer of the upper gastrointestinal tract. This study aimed to assess whether and to what extent a negative upper endoscopy in patients with GERD is associated with decreased incidence and mortality in upper gastrointestinal cancer (ie, esophageal, gastric, or duodenal cancer). METHODS: We conducted a population-based cohort study of all patients with newly diagnosed GERD between July 1, 1979 and December 31, 2018 in Denmark, Finland, Norway, and Sweden. The exposure, negative upper endoscopy, was examined as a time-varying exposure, where participants contributed unexposed person-time from GERD diagnosis until screened and exposed person-time from the negative upper endoscopy. The incidence and mortality in upper gastrointestinal cancer were assessed using parametric flexible models, providing adjusted hazard ratios (HRs) with 95% confidence intervals (CIs). RESULTS: Among 1,062,740 patients with GERD (median age 58 years; 52% were women) followed for a mean of 7.0 person-years, 5324 (0.5%) developed upper gastrointestinal cancer and 4465 (0.4%) died from such cancer. Patients who had a negative upper endoscopy had a 55% decreased risk of upper gastrointestinal cancer compared with those who did not undergo endoscopy (HR, 0.45; 95% CI, 0.43-0.48), a decrease that was more pronounced during more recent years (HR, 0.34; 95% CI, 0.30-0.38 from 2008 onward), and was otherwise stable across sex and age groups. The corresponding reduction in upper gastrointestinal mortality among patients with upper endoscopy was 61% (adjusted HR, 0.39; 95% CI, 0.37-0.42). The risk reduction after a negative upper endoscopy in incidence and mortality lasted for 5 and at least 10 years, respectively. CONCLUSIONS: Negative upper endoscopy is associated with strong and long-lasting decreases in incidence and mortality in upper gastrointestinal cancer in patients with GERD.Peer reviewe

Antireflux surgery and risk of lung cancer by histological type in a multinational cohort study

Introduction: Airway micro-aspiration might contribute to the proposed associations between gastroesophageal reflux disease (GERD) and some lung diseases, including lung cancer. This study aimed to examine the hypothesis that antireflux surgery decreases the risk of small cell carcinoma, squamous cell carcinoma and adenocarcinoma of the lung differently depending on their location in relation to micro-aspiration. Methods: Population-based cohort study including patients having undergone antireflux surgery during 1980-2014 in Denmark, Finland, Iceland, Norway or Sweden. Patients having undergone antireflux surgery were compared with two groups: 1) the corresponding background population, by calculating standardised incidence ratios (SIRs) with 95% confidence intervals (CIs) and 2) non-operated GERD-patients, by calculating hazard ratios (HRs) with 95% CIs using multivariable Cox regression with adjustment for sex, age, calendar period, country, chronic obstructive pulmonary disease and obesity diagnosis or type 2 diabetes. Results: Among all 812,617 GERD-patients, 46,996 (5.8%) had undergone antireflux surgery. The SIRs were statistically significantly decreased for small cell carcinoma (SIR = 0.57, 95% CI 0.41-0.77) and squamous cell carcinoma (SIR = 0.75, 95% CI 0.60-0.92), but not for adenocarcinoma of the lung (SIR = 0.90, 95% CI 0.76-1.06). The HRs were also below unity for small cell carcinoma (HR = 0.63, 95% CI 0.44-0.90) and squamous cell carcinoma (HR = 0.80, 95% CI 0.62-1.03), but not for adenocarcinoma of the lung (HR = 1.03, 95% CI 0.84-1.26). Analyses restricted to patients with objective GERD (reflux oesophagitis or Barrett's oesophagus) showed similar results. Conclusions: This all-Nordic study indicates that patients who undergo antireflux surgery are at decreased risk of small cell carcinoma and squamous cell carcinoma of the lung, but not of adenocarcinoma of the lung. (C) 2020 The Author(s). Published by Elsevier Ltd.Peer reviewe

Mortality, Reoperation, and Hospital Stay Within 90 Days of Primary and Secondary Antireflux Surgery in a Population-Based Multinational Study

BACKGROUND & AIMS: Absolute rates and risk factors of short-term outcomes after antireflux surgery remain largely unknown. We aimed to clarify absolute risks and risk factors for poor 90-day outcomes of primary laparoscopic and secondary antireflux surgery. METHODS: This population-based cohort study included patients who had primary laparoscopic or secondary antireflux surgery in the 5 Nordic countries in 2000-2018. In addition to absolute rates, we analyzed age, sex, comorbidity, hospital volume, and calendar period in relation to all-cause 90 day mortality (main outcome), 90-day reoperation, and prolonged hospital stay (>= 2 days over median stay). Multivariable logistic regression provided odds ratios (ORs) with 95% confidence intervals (95% CI), adjusted for confounders. RESULTS: Among 26,193 patients who underwent primary laparoscopic antireflux surgery, postoperative 90-day mortality and 90-day reoperation rates were 0.13% (n = 35) and 3.0% (n = 750), respectively. The corresponding rates after secondary antireflux surgery (n = 1 618) were 0.19% (n = 3) and 6.2% (n = 94). Higher age (56-80 years vs 18-42 years: OR, 2.66; 95% CI 1.03-6.85) and comorbidity (Charlson Comorbidity Index >= 2 vs 0: OR, 6.25; 95% CI 2.42-16.14) increased risk of 90-day mortality after primary surgery, and higher hospital volume suggested a decreased risk (highest vs lowest tertile: OR, 0.58; 95% CI, 0.22-1.57). Comorbidity increased the risk of 90-day reoperation. Higher age and comorbidity increased risk of prolonged hospital stay after both primary and secondary surgery. Higher annual hospital volume decreased the risk of prolonged hospital stay after primary surgery (highest vs lowest tertile: OR, 0.74; 95% CI, 0.67-0.80). CONCLUSION: These findings suggest that laparoscopic antireflux surgery has an overall favorable safety profile in the treatment of gastro-esophageal reflux disease, particularly in younger patients without severe comorbidity who undergo surgery at high-volume centers.Peer reviewe

Fundamental Studies In the Lamb-Wave Interaction Between Piezoelectric Wafer Active Sensor and Host Structure During Structural Health Monitoring

The scope of my research was to develop a better understanding of the engineering variables that influence the interaction of PWAS with structure during activation of the transducer. This is a key feature needed to develop more power/energy efficient structural health monitoring (SHM) systems. SHM is the field of engineering that determines the health of a structure while it is in service. Active SHM can be performed through piezoelectric transducers such as piezoelectric wafer active sensors (PWAS) that can be permanently attached to the structure through a bonding layer. PWAS transducers can actively interrogate the structure by exciting and receiving Lamb waves propagating in the structure or by passively listen to changes in the structure. PWAS-structure interaction modeling is fundamental in order to achieve single mode excitation, i.e., tuning, a requirement for most of the SHM algorithms (time reversal, phase-array, and imaging). To achieve our research goal, we had to go beyond the current state of the art in modeling and understanding the load transfer from PWAS to the structure. The existing modeling methods rely on the low frequency assumption of axial/flexural waves only. This assumption is not true in the high frequency range of ultrasonic SHM applications. We derived, through the normal mode expansion methods (NME), the interfacial shear stress, hence, the load transfer from the PWAS to the structure through the bond layer, without limitations on the frequency and the number of modes. This allowed us to derive more accurate predictions of the tuning between PWAS and Lamb waves which compared very well with experimental measurements. This dissertation is constructed in three major parts. In Part I, we developed a generic formulation for ultrasonic guided waves in thin wall structures. The formulation is generic because, unlike many authors, in many parts of our derivation (power flow, reciprocity theorem, orthogonality, etc.) we stayed away from specifying the actual mathematical expressions of the guided wave modes and maintained a generic formulation throughout. In Part II, we addressed some unresolved issues of the PWAS SHM predictive modeling. We extended the NME theory to the case of PWAS bonded to or embedded in the structure. We developed the shear layer coupling between PWAS and structure using N generic guided wave modes and solving the resulting integro-differential equation for shear lag transfer. We applied these results to predicting the tuning between guided waves and PWAS and obtained excellent agreement with experimental results. Another novel aspect covered in this dissertation is that of guided waves in composite materials. The increasing use of composites in aeronautical and space applications makes it important to extend SHM theory to such materials. For this reason, the NME theory is extended to the case of composites. We developed a generic formulation for the tuning curves that was not directly dependent on the composite layup and can be easily extended to various composite formulations. We conducted carefully-planned experiments on composites with different orientations. The comparison between our predictions and experiments was quite good. In Part III, SHM applications and related issues are addressed. We discussed the reliability of SHM systems and the lack of specifications for quality SHM inspections with particular focus on the case of composites SHM. We determined experimentally the ability of PWAS to detect damage in various composite specimens. We tested the performance of the PWAS for damage detection on composite plates, on unidirectional composite strips, on quasi-isotropic plates, on lap-joints junctions, and composite tank sections. We also tested the ability of PWAS transducers to operate under extreme environments and high stress conditions, i.e. the survivability of PWAS-based SHM. We proved the durability of the entire PWAS-based SHM system under various different load conditions. We also tested the influence of bond degradation on PWAS electrical capacitance as installed on the structure, which gives a measure of the quality of the PWAS installation, a key feature in PWAS-based SHM. We developed theoretical models for shear horizontal waves scattering from a crack and Lamb waves scattering from change in material properties. We studied the acoustic emission (AE) in infinite plate and we used NME to model AE phenomena