Elinor Ytterstad

Mortality after the death of a spouse in Norway.

Background: Previous studies on mortality of widowed individuals have produced varying estimates of mortality after the death of a spouse. This variation is because of the various data types used and methodologies applied, as well as to the failure to account for sources of bias. Methods: We followed all married individuals in Norway (1,801,456 individuals) for 32 years, and information on marital status and death was collected for use in a new application of survival analysis in this field of research. Results: We compared mortality of widowed individuals with that of married individuals. Widowed men and women had hazard ratios of 1.34 (95% confidence interval 1.31, 1.36) and 1.29 (1.26, 1.31), respectively, for the first year after spousal death. For the same period, values were highest in ages 60–64 years with 1.78 (1.57, 1.98) in men and 1.50 (1.35, 1.65) in women. Values dropped gradually with age and more rapidly in men than women to a low for ages 85–89 years of 1.24 (1.19, 1.29) in men and 1.25 (1.20, 1.31) in women. The risk was much higher 1 to 7 days after spousal death (1.69 [1.49, 1.88] in men and 1.76 [1.56, 1.96] in women), then it dropped during the first year and from then on remained stable to year 10, which was the last year considered. Conclusion: A considerable excess mortality risk was observed in widowed men and women from immediately after the loss of a spouse and for the next 10 years.

Property-Dependent Analysis of Aligned Proteins from Two Or More Populations.

Multiple sequence alignments can provide information for comparative analyses of proteins and protein populations. We present some statistical trend-tests that can be used when an aligned data set can be divided into two or more populations based on phenotypic traits such as preference of temperature, pH, salt concentration or pressure. The approach is based on estimation and analysis of the variation between the values of physicochemical parameters at positions of the sequence alignment. Monotonic trends are detected by applying a cumulative Mann-Kendall test. The method is found to be useful to identify significant physicochemical mechanisms behind adaptation to extreme environments and uncover molecular differences between mesophile and extremophile organisms. A filtering technique is also presented to visualize the underlying structure in the data. All the comparative statistical methods are available in the toolbox DeltaProt.

Increased risk of death immediately after losing a spouse: Cause-specific mortality following widowhood in Norway.

OBJECTIVE This paper examines the short-term risk of cause-specific death following widowhood. METHOD We followed all individuals registered as married in Norway in 1975 for marital status and mortality until 2006. Widowed individuals were followed for mortality for 7years following widowhood. Causes of death were categorized into five cause-groups. Life tables were used in survival analyses. RESULTS Deaths among the widowed were most frequent in the week following widowhood. In this week and compared to married individuals, there were more deaths including those from malignant cancer in men (hazard ratio (HR) of 1.51; 95% CI: 1.12, 1.89), from external causes in men (HR=3.64; 95% CI: 2.01, 5.28), and from respiratory diseases (HR=2.18; 95% CI: 1.52, 2.84 in men and HR=3.18; 95% CI: 2.26, 4.09 in women). A majority of respiratory deaths were from pneumonia. Thereafter excess mortality among the widowed dropped gradually. Although these numbers stabilized, they were still elevated in year 7. Excess mortality was particularly high in the youngest age group considered (55-64years) and decreased with age, though more so in men than in women. Only a few more widowed individuals than expected died of a condition in the same cause-group as their spouses. CONCLUSION A novel finding was that excess deaths in the week following widowhood also were from cancer and respiratory diseases. Men in the youngest age group seemed most vulnerable. Prevention should be considered directly after the death of a spouse, and measures should be aimed at virtually all causes of death.

COPD in primary lung cancer patients: prevalence and mortality.

Background Previous studies have relied on international spirometry criteria to diagnose COPD in patients with lung cancer without considering the effect lung cancer might have on spirometric results. The aim of this study was to examine the prevalence of COPD and emphysema at the time of primary lung cancer diagnosis and to examine factors associated with survival. Materials and methods Medical records, pulmonary function tests, and computed tomography scans were used to determine the presence of COPD and emphysema in patients diagnosed with primary lung cancer at the University Hospital of North Norway in 2008–2010. Results Among the 174 lung cancer patients, 69% had COPD or emphysema (39% with COPD, 59% with emphysema; male:female ratio 101:73). Neither COPD nor emphysema were significantly associated with lung cancer mortality, whereas patients with non-small-cell lung cancer other than adenocarcinoma and squamous cell carcinoma had a risk of lung cancer mortality that was more than four times higher than that of patients with small-cell lung cancer (hazard ratio [HR] 4.19, 95% confidence interval [CI] 1.56–11.25). Females had a lower risk of lung cancer mortality than males (HR 0.63, 95% CI 0.42–0.94), and patients aged ≥75 years had a risk that was twice that of patients aged <75 years (HR 2.48, 95% CI 1.59–3.87). Low partial arterial oxygen pressure (4.0–8.4 kPa) increased the risk of lung cancer mortality (HR 2.26, 95% CI 1.29–3.96). So did low partial arterial carbon dioxide pressure (3.0–4.9 kPa) among stage IV lung cancer patients (HR 2.23, 95% CI 1.29–3.85). Several patients with respiratory failure had previously been diagnosed with COPD. Conclusion The observed prevalence of COPD was lower than that in previous studies. Neither COPD nor emphysema were significantly associated with lung cancer mortality.

Research Article: Environmental adaptation of proteins: Regression models with simple physicochemical properties

Bio-sequences from ortholog proteins are well suited for statistical inference when the sequences can be divided into ordinal groups based on known environmental features or traits of the host organisms. In this paper two new regression models are described for extracting proteomic trends of extreme environments. The approach is based on physicochemical properties of the amino acids, and may also utilise stratification of the data. We are especially looking for connections of temperature adaptation between the organism and its molecular level. To show the applicability of the methods, we present analyses of genomic data from proteobacteria orders, where we examine the cold adaptation of membrane proteins, intracellular proteins, and the enzyme endonuclease I. Our results confirm earlier findings that redistribution of charge and increase of surface hydrophobicity might be some of the most important signatures for cold adaptation.

Inferring weak adaptations and selection biases in proteins from composition and substitution matrices

There is a desire for increasing use of statistical methods in analysing the growing amounts of bio-sequences. We present statistical methods that are useful when a protein alignment can be divided into two groups based on known features or traits. The approach is based on stratification of the data, and to show the applicability of the methods we present analysis of genomic data from proteobacteria orders. A dataset of 25 periplasmic/extracellular bacterial enzyme endonuclease I proteins was compiled to identify genotypic characteristics that separate the cold adapted proteins from ortholog sequences with a higher optimal growth temperature. Our results reveal that the cold adapted protein has a significantly more positively charged exterior. Life in a cold climate seems to be enabled by many minor structural modifications rather than a particular amino acid substitution. Redistribution of charge might be one of the most important signatures for cold adaptation.

Leakage from medically-certified to self-certified workplace absence among norwegian employees

ABSTRACT There are two different kinds of sickness absence in Norway: self-certified absence (SCA), and medically-certified absence (MCA). In this study of 6437 Norwegian employees, we applied logistic regression models for a dichotomous SCA variable on initially 38 independent variables including age and gender. Our findings showed that employees reporting long-term health issues but no record of MCA in the past 12 months (9.4% of the employees), had significantly higher odds of SCA than other employees. We claim that this constitutes a leakage of workplace absence from MCA to SCA, since these employees have long-term health issues. In addition, we found that women in this group were more likely to reduce their workload to part-time jobs, compared to other women. We suggest that basing MCA on diagnoses from a certified list contributes to leakage of employees with specific characteristics from MCA to SCA.

Directionality of cross-linguistic influence: Which referring choices do bilingual Ukrainian–English children make?

Aims and research questions: This paper presents a new study addressing the issue of cross-linguistic influence in acquisition of referring expressions. The main research question is how to predict directionality of this influence in a dual language development. Methodology: The method is an elicited production task. We consider the phenomenon of direct object referring choices, i.e. noun, pronoun and null element, in a ‘null-object’–‘overt-object’ language pair (Ukrainian and English). Data and Analysis: Participants of the experiment are 4–6-year-old Ukrainian–English bilinguals (N20) and Ukrainian monolinguals (N21). The data are analyzed in the statistical program R, utilizing the R-library function lme4. The results are presented as odds ratios (ORs) of each direct object type. Findings: Our data reveal that while there is no significant difference in Ukrainian object types in most of the age groups, there is a considerable amount of null object usage in English at the ages of four to five. Originality: The innovative nature of this study lies in: (i) the consideration of a licit object omission at a later stage of language development (from 4 to 6 years of age); (ii) the examination of an under-investigated language combination (i.e. English and Ukrainian); and (iii) the innovative approach to linguistic data analysis (e.g. comparing OR values). Implications: Our findings suggest that the directionality of influence in dual language acquisition depends on the developmental stage, language-specific means of syntax–pragmatics interaction, and extra-linguistic input-related factors. At the early stages of development, the null-object language is likely to influence the overt-object language, especially under conditions of limited exposure to the latter.

Exploring Personality and Readiness to Change in Patients With Substance Use Disorders With and Without ADHD

Objective: To explore personality and readiness to change among substance use disorders (SUD) patients with and without ADHD. Method: SUD + ADHD versus SUD − ADHD patients consecutively entering treatment between 2010 and 2012 were compared concerning personality (Temperament and Character Inventory) and readiness to change (Stages of Change Readiness and Treatment Eagerness Scale). Results: Among 103 SUD patients (76 men, age M = 43.3, SD = 11.1), 16 (15.5%) were diagnosed with ADHD. SUD + ADHD patients reported significantly elevated eagerness to effort (p = .008) compared with SUD − ADHD patients, who reported significantly elevated fear of uncertainty (p < .000). SUD + ADHD patients reported higher ambition (p = .025), self-forgetfulness (p = .029), and lower recognition (p = .022). They were younger (p = .019) and showed more often amphetamine addiction (p = .022) compared with SUD − ADHD patients. Conclusion: The distinct characteristics found in SUD + ADHD and SUD − ADHD patients underline the need for differentiated treatment interventions.