Characterization of SARS-CoV-2 Variants in Military and Civilian Personnel of an Air Force Airport during Three Pandemic Waves in Italy.

We investigated SARS-CoV-2 variants circulating, from November 2020 to March 2022, among military and civilian personnel at an Air Force airport in Italy in order to classify viral isolates in a potential hotspot for virus spread. Positive samples were subjected to Next-Generation Sequencing (NGS) of the whole viral genome and Sanger sequencing of the spike coding region. Phylogenetic analysis classified viral isolates and traced their evolutionary relationships. Clusters were identified using 70% cut-off. Sequencing methods yielded comparable results in terms of variant classification. In 2020 and 2021, we identified several variants, including B.1.258 (4/67), B.1.177 (9/67), Alpha (B.1.1.7, 9/67), Gamma (P.1.1, 4/67), and Delta (4/67). In 2022, only Omicron and its sub-lineage variants were observed (37/67). SARS-CoV-2 isolates were screened to detect naturally occurring resistance in genomic regions, the target of new therapies, comparing them to the Wuhan Hu-1 reference strain. Interestingly, 2/30 non-Omicron isolates carried the G15S 3CLpro substitution responsible for reduced susceptibility to protease inhibitors. On the other hand, Omicron isolates carried unusual substitutions A1803V, D1809N, and A949T on PLpro, and the D216N on 3CLpro. Finally, the P323L substitution on RdRp coding regions was not associated with the mutational pattern related to polymerase inhibitor resistance. This study highlights the importance of continuous genomic surveillance to monitor SARS-CoV-2 evolution in the general population, as well as in restricted communities.

Neural networks underlying visual illusions: An activation likelihood estimation meta-analysis.

Visual illusions have long been used to study visual perception and contextual integration. Neuroimaging studies employ illusions to identify the brain regions involved in visual perception and how they interact. We conducted an Activation Likelihood Estimation (ALE) meta-analysis and meta-analytic connectivity modeling on fMRI studies using static and motion illusions to reveal the neural signatures of illusory processing and to investigate the degree to which different areas are commonly recruited in perceptual inference. The resulting networks encompass ventral and dorsal regions, including the inferior and middle occipital cortices bilaterally in both types of illusions. The static and motion illusion networks selectively included the right posterior parietal cortex and the ventral premotor cortex respectively. Overall, these results describe a network of areas crucially involved in perceptual inference relying on feed-back and feed-forward interactions between areas of the ventral and dorsal visual pathways. The same network is proposed to be involved in hallucinogenic symptoms characteristic of schizophrenia and other disorders, with crucial implications in the use of illusions as biomarkers.

The Effect of Cognitive Style on Individual Differences in Prismatic Adaptation: A Pilot Study.

Prism adaptation (PA) is a well-known and widely used technique for rehabilitating unilateral spatial neglect and studying sensory-motor plasticity. However, there is conflicting evidence in the literature regarding its effectiveness which may arise from differences in the type of prisms used, clinical characteristics of the patients, and the procedure used in training. Individual differences may play a role in PA effectiveness in rehabilitating neglect, affecting both its development and its effects. Field-dependent/independent cognitive style is a pervasive characteristic of individual functioning, affecting how environmental information is processed. Here, we tested the hypothesis that cognitive style plays a role in PA efficacy by submitting to a protocol of prism adaptation to 38 health participants, who were classified as field-dependent (FD, N = 19) or field-independent (FI, N = 19), by using the Embedded Figure Test. Results show that during the exposure phase, FI individuals needed a lesser number of pointing movements to reduce the deviation error than FD individuals. However, there are no differences in the extinction of sensory-motor and cognitive after-effects. These results suggest that prismatic adaptation is affected by individuals' cognitive style since FI individuals will need fewer trials to reach adaptation and this could explain why using this rehabilitation technique with a unique, standard protocol is not always effective.

Diagnostic accuracy of a SARS-CoV-2 rapid antigen test among military and civilian personnel of an Air Force airport in central Italy.

BACKGROUND: Most SARS-CoV-2 rapid antigen detection tests (RADTs) validation studies have been performed on specimens from COVID-19 patients and negative controls or from mostly symptomatic individuals. Herein we evaluated the diagnostic accuracy of AFIAS COVID-19 Ag, hereinafter denominated as AFIAS, during a COVID-19 screening program surveillance testing conducted among personnel of an Italian military airport. METHODS: Nasopharyngeal swabs (NPSs) were collected from study participants and were analysed by both AFIAS and RT-PCR assay. A questionnaire collecting demographic and exposure data were administered to all participants. AFIAS accuracy parameters including Cohen's kappa (K) were determined. RESULTS: Overall, from November 2020 to April 2021, 1294 (NPSs) were collected from 1183 participants (88.6% males, 11.4% females; mean age were 41.3, median age 42). Forty-nine NPSs (3.78%) were positive by RT-PCR, while 54 NPSs were positive by AFIAS. Overall baseline sensitivity, specificity, positive and negative predictive values were 0.633, 0.981, 0.574, 0.985, respectively and K was 0.585 (moderate). AFIAS sensitivity tended to be higher for NPSs with higher viral load. A higher sensitivity (0.944) compared to the overall baseline sensitivity (0.633) was also found for NPSs from participants with COVID-19 compatible symptoms, for which K was 0.891 (almost perfect). Instead, AFIAS sensitivity was quite poor for NPSs from asymptomatic participants. Most false negative NPSs in this group had moderate viral load. CONCLUSION: Overall, AFIAS showed high specificity but only moderate sensitivity, mainly because of the high proportion of asymptomatic participants. However, AFIAS showed good sensitivity for NPSs with high viral load and nearly optimal accuracy parameters for NPSs from participants with COVID-19 compatible symptoms. Thus, taking into consideration its performance features, this test can be useful for COVID-19 case identification and management as well as for infection control.

Where Am I? Searching for the Tangle in the Developmental Topographical Disorientation.

The Developmental Topographical Disorientation (DTD) is a pathological condition that impairs an individual's ability to orient in space, even in the most familiar environments. It is a lifelong selective condition in individuals without brain damage or without impaired general cognitive functions. Here, we aimed at characterizing 54 individuals with DTD identified in a previous study, aged between 18 and 35 years and assessed through a 4-year-long online survey. To this purpose, we compared them with 54 matched healthy participants. We described the demographics, sense of direction, town knowledge, navigational strategies, left-right confusion as well as agnosic disorders (for landmarks, faces and objects). This novel study attempts to characterize the phenotype of DTD, providing an important contribution to the worldwide definition of a condition that was first described only 13 years ago, but which, considering the growing number of cases complaining of the disorder, deserves continuous and increasing attention.

"Where am I?" A snapshot of the developmental topographical disorientation among young Italian adults.

In the last decade, several cases affected by Developmental Topographical Disorientation (DTD) have been described. DTD consists of a neurodevelopmental disorder affecting the ability to orient in the environment despite well-preserved cognitive functions, and in the absence of a brain lesion or other neurological or psychiatric conditions. Described cases showed different impairments in navigational skills ranging from topographic memory deficits to landmark agnosia. All cases lacked a mental representation of the environment that would allow them to use high-order spatial orientation strategies. In addition to the single case studies, a group study performed in Canada showed that the disorder is more widespread than imagined. The present work intends to investigate the occurrence of the disorder in 1,698 young Italian participants. The sample is deliberately composed of individuals aged between 18 and 35 years to exclude people who could manifest the loss of the ability to navigate as a result of an onset of cognitive decline. The sample was collected between 2016 and 2019 using the Qualtrics platform, by which the Familiarity and Spatial Cognitive Style Scale and anamnestic interview were administered. The data showed that the disorder is present in 3% of the sample and that the sense of direction is closely related to town knowledge, navigational strategies adopted, and gender. In general, males use more complex navigational strategies than females, although DTD is more prevalent in males than in females, in line with the already described cases. Finally, the paper discusses which protective factors can reduce DTD onset and which intervention measures should be implemented to prevent the spread of navigational disorders, which severely impact individuals' autonomy and social relationships.

GPS Digital Nudge to Limit Road Crashes in Non-Expert Drivers.

Many automotive industries are developing technologies to assist human drivers in suggesting wiser choices to improve drivers' behaviour. The technology that makes use of this modality is defined as a "digital nudge". An example of a digital nudge is the GPS that is installed on smartphones. Some studies have demonstrated that the use of GPS negatively affects environmental learning because of the transformation of some spatial skills. The main purpose of this study was to investigate the use of the GPS nudge and its relationship with spatial ability, together with its function in supporting the driving behaviour of non-expert drivers, in order to reduce the number of road crashes. A total of 88 non-expert drivers (M age = 21 years) filled in questionnaires and carried out tasks to measure spatial abilities, sense of direction, driver behaviour, and six different real-life driving scenarios. The results reveal that the higher the spatial skills are, the greater the GPS use is, and that drivers who use GPS improve their sense of direction. Moreover, people with high visuospatial abilities use GPS more extensively. Finally, young drivers do not consider the GPS aid to be useful when they have no time pressure. The results are discussed by taking into account the familiarity-and-spatial-ability model.

A Controversial Assessment of Fitness to Fly After a Traumatic Brain Injury.

INTRODUCTION: After traumatic brain injury (TBI), cognitive, behavioral alterations and seizures frequently occur. Beside instrumental examinations, neuropsychological testing is the common clinical practice for detecting cognitive deficits. However, in highly skilled individuals, subtle changes with a large impact on fitness to fly may be neglected.CASE REPORT: A 28-yr-old Italian Air Force pilot with almost 700 flying hours suffered a TBI. After 2 yr of cognitive retraining programs, as the neuropsychological evaluation executed in a public hospital was within the standards and repeated EEGs had all been normal, the pilot was allowed to resume flying duties. During the refresh flight training, he was not considered proficient for solo flight and was again referred to the Institute of Aerospace Medicine (IMAS), where, due to the absence of a neuropsychologist, the pilot was referred to a public hospital. Again, he was within the normal range and received a fitness to fly with limitations. Nevertheless, the flight instructors noticed the presence of cyclic errors. Consequently, he was sent for a third time to the IMAS, where the cooperation between a neuropsychologist and a flight surgeon allowed a tailored testing.DISCUSSION: With a proper evaluation, the subject showed deficits in topographic visuospatial learning and in prospective memory. After 5 yr, he was finally declared permanently unfit to fly. Specific neuropsychological batteries, simulated flight tests, and aeromedical evaluations are described here.Verde P, Guadagno AG, D'Angelo A, Vitalone R, Di Vita A, Piccardi L. A controversial assessment of fitness to fly after a traumatic brain injury. Aerosp Med Hum Perform. 2022; 93(2):116-122.

Renal effect of severe hypoxia evaluated By NGAL measurements: An in vivo and in vitro study.

PURPOSE: To investigate possible renal damage in healthy men exposed to extreme hypobaric hypoxia, using urinary Neutrophil Gelatinase-Associated Lipocalin (NGAL) concentration as biomarker. The value of NGAL as a biomarker of proximal tubular cell damage under hypoxic conditions was also tested in vitro experiments. METHODS: NGAL was assayed in a cohort of air cadets (n = 16) exposed to hypobaric hypoxia in a hypobaric chamber during their training program. In all subjects, urine creatinine (Cr) and urinary NGAL levels were measured immediately before, 3, and 24 h after hypobaric environment exposure. Three in vitro experiments using proximal tubular cell cultures were also performed to measure NGAL gene expression, NGAL secretion in the culture medium and to evaluate apoptosis under two cycles of hypoxia and reoxygenation. RESULTS: In the in vivo study, geometric means of urinary NGAL/Cr ratio measured 24 h after hypobaric hypoxia in the hypobaric chamber were significantly lower than baseline values (13.4 vs 25.9 ng/mg, p = 0.01). In cell cultures, hypoxia down-regulated NGAL gene expression without significantly changing NGAL secretion in the culture medium. Hypoxia significantly increased the percentage of apoptotic/necrotic cells, especially after the second hypoxia-reoxygenation cycle. CONCLUSIONS: Exposure to hypobaric-hypoxic environments does not cause significant and irreversible renal tubular injury in vivo and in vitro, except than in a late stage. The hypoxic insult does not seem to be mirrored by an increase of urinary NGAL in healthy men nor of NGAL gene expression in HK-2 cell culture or secretion in the culture medium in the in vitro conditions reported in the present study.

Neonatal Diabetes in Patients Affected by Liang-Wang Syndrome Carrying KCNMA1 Variant p.(Gly375Arg) Suggest a Potential Role of Ca2+ and Voltage-Activated K+ Channel Activity in Human Insulin Secretion.

Liang-Wang syndrome (LIWAS) is a polymalformative syndrome first described in 2019 caused by heterozygous mutation of the KCNMA1 gene encoding the Ca2+ and voltage-activated K+ channel (BKC). The KCNMA1 variant p.(Gly356Arg) abolishes the function of BKC and blocks the generation of K+ current. The phenotype of this variant includes developmental delay, and visceral and connective tissue malformations. So far, only three cases of LWAS have been described, one of which also had neonatal diabetes (ND). We present the case of a newborn affected by LIWAS carrying the p.(Gly375Arg) variant who manifested diabetes in the first week of life. The description of our case strongly increases the frequency of ND in LIWAS patients and suggests a role of BK inactivation in human insulin secretion. The knowledge on the role of BKC in insulin secretion is very poor. Analyzing the possible mechanisms that could explain the association of LIWAS with ND, we speculate that BK inactivation might impair insulin secretion through the alteration of ion-dependent membrane activities and mitochondrial functions in ß-cells, as well as the impaired intra-islet vessel reactivity.

Do Advanced Spatial Strategies Depend on the Number of Flight Hours? The Case of Military Pilots.

BACKGROUND: Military pilots show advanced visuospatial skills. Previous studies demonstrate that they are better at mentally rotating a target, taking different perspectives, estimating distances and planning travel and have a topographic memory. Here, we compared navigational cognitive styles between military pilots and people without flight experience. Pilots were expected to be more survey-style users than nonpilots, showing more advanced navigational strategies. METHOD: A total of 106 military jet pilots from the Italian Air Force and 92 nonpilots from the general population matched for education with the pilots were enrolled to investigate group differences in navigational styles. The participants were asked to perform a reduced version of the Spatial Cognitive Style Test (SCST), consisting of six tasks that allow us to distinguish individuals in terms of landmark (people orient themselves by using a figurative memory for environmental objects), route (people use an egocentric representation of the space) and survey (people have a map-like representation of the space) user styles. RESULTS: In line with our hypothesis, military pilots mainly adopt the survey style, whereas nonpilots mainly adopt the route style. In addition, pilots outperformed nonpilots in both the 3D Rotation Task and Map Description Task. CONCLUSIONS: Military flight expertise influences some aspects of spatial ability, leading to enhanced human navigation. However, it must be considered that they are a population whose navigational skills were already high at the time of selection at the academy before formal training began.

An unusual spirometric shape that you must not forget.

An anomalous spirometric pattern can initiate a diagnostic path leading to the finding of a congenital vascular malformation. The flow-volume curve may hide a nonrespiratory pathology. Spirometry is not just asthma or COPD. http://bit.ly/30iHRCp.

Total Ankle Replacement in a Military Jet Pilot.

INTRODUCTION: A total ankle replacement in a jet pilot after an open, high-energy foot and ankle fracture and dislocation with talar extrusion in a plane crash was carefully evaluated before considering fitness to fly.CASE REPORT: A 33-yr-old male test pilot of the Italian Air Force was involved in a plane crash and reported an open high-energy fracture/dislocation of the right ankle, with the expulsion of the right talus due to the impact, and other fractures. A titanium replica was inserted inside the ankle. However, the patient suffered from intolerable pain and developed arthritic changes in the cartilage of the tibial plafond. For these reasons, a decision was made to perform a custom-made total ankle replacement.DISCUSSION: The 2-yr follow-up after the last operation and the evaluation of the pilot's fitness to fly are reported in this case study. The pilot was assessed fit to fly, including high performance military aircrafts.Verde P, Guardigli S, Morgagni F, Roberts S, Monopoli D, Scala A. Total ankle replacement in a military jet pilot. Aerosp Med Hum Perform. 2020; 91(7):597-603.

Does spatial cognitive style affect how navigational strategy is planned?

People orient themselves in the environment using three different, hierarchically organized, spatial cognitive styles: landmark, route, and survey. Landmark style is based on a representation encompassing only visual information (terrain features); route style is based on a representation that connects landmarks and routes using an egocentric (body-centred) frame of reference; survey style is based on a global map-like representation that mainly involves an allocentric (world-centred) frame of reference. This study was aimed at investigating whether individual spatial cognitive style affected the way to plan a path when searching for a lost object. Participants with landmark, route, and survey style were assessed with an ecological navigational planning task (the Key Search Task), which required planning a strategy to search for the lost key in a hypothetical wide squared field. Results showed that spatial cognitive styles were associated to different navigational planning strategies, although the time to complete the Key Search Task was comparable across the styles. As revealed by the Key Search Task score, survey style individuals were the best navigational planners, route style individuals were less efficient and landmark style individuals were the least efficient. These results suggest that spatial cognitive style has effects on navigational planning. Implications for clinical settings, such as for developmental topographical disorientation, are discussed.

Effects of oral contraceptives and natural menstrual cycling on environmental learning.

BACKGROUND: Endogenous ovarian hormones as well as exogenous oestradiol and progesterone play an important role in cognitive processing. Specifically, these hormones play a role in different aspects of memory, both in terms of storage capacity and temporal duration of the mnemonic track. These hormones also have various effects on different types of memory (i.e., verbal, visuo-spatial, prospective). This study investigated the effects of hormones on topographic memory, a type of memory specifically needed to recall a pathway and to acquire spatial information about locations, distances, and directions. METHODS: We compared 25 naturally cycling women (NCW) in two different cycling phases, the early follicular phase (4th - 5th days) and the mid-luteal phase (20th-21st days), with 26 women taking oral contraceptives (OC) tested in the active pill phase (20th to 21st day of OC cycle) and the inactive pill phase (2nd to 4th day of OC cycle). Both groups performed the Walking Corsi Test to assess topographic memory in their respective cycling phases. Women were instructed to learn an eight-step sequence path and recall the path five minutes later. RESULTS: We found that the two groups differed in terms of learning the 8-step sequence path; OC users were always better (4-5 days vs. 20-21 days) than NCW. No differences emerged in the delayed recall of the same path. CONCLUSIONS: As already observed in other memory domains (i.e., verbal memory, emotional memory), OC users showed an advantage in terms of topographic learning. Our results might be explained by hormonal mechanisms and may suggest the future application of OC in women with topographic disorders or visuo-spatial difficulties.

Spatial Orientation and Directional Judgments in Pilots vs. Nonpilots.

BACKGROUND: Reading a map requires the ability to judge one's position in a large-scale space from information presented in a small-scale representation. Individuals are more accurate and faster in making judgments when the "up" direction on the map is the same as the "forward" direction of the environment, which is when a map is aligned with the perspective of the spatial layout they have learned (alignment effect). The aim of this study was to explore whether military pilots, who have high spatial abilities, would not show the alignment effect compared with nonpilots. METHODS: Recruited were 20 military pilots and 20 nonpilots. Mean flight hours were 418.75. Nonpilots without flight experience were matched for age and education with pilots. Subjects were asked to learn a map and to perform directional judgments to verify whether the alignment effect was present considering absolute angular errors. RESULTS: An ANOVA for mixed designs on absolute angular errors revealed a main "group" effect: pilots performed better than nonpilots (pilots: M = 22.60 ± 5.57; nonpilots: M = 82.59 ± 5.56). A main "directional judgments" effect was also observed: aligned judgements were easier than contra-aligned judgements (aligned, M = 9.277 ± 0.938; contra-aligned, M = 11.004 ± 0.805). ANOVA showed a significant "group × directional judgments" interaction: post hoc comparison showed that contra-aligned were more difficult than aligned judgments for nonpilots. DISCUSSION: High visuo-spatial abilities preserved pilots from having alignment effect bias. They performed directional judgments equally well, being less influenced by the increased cognitive effort requested by the changing perspective.Verde P, Angelino G, Piccolo F, Carrozzo P, Bottiglieri A, Lugli L, Piccardi L, Nori R. Spatial orientation and directional judgments in pilots vs. nonpilots. Aerosp Med Hum Perform. 2018; 89(10):857-862.

Effect of professional expertise and exposure to everyday life decision-making on moral choices.

Moral sense is defined as a feeling of fairness or unfairness of an action that knowingly causes harm to people other than the subject. It is crucial in determining human behavior and becomes pivotal in operational environments. Here we assessed whether professional daily life experience in an operational environment affects moral judgment by asking 41 military pilots of the Italian Air Force (P) and 69 controls (C) to solve 40 moral dilemmas. We found that P gave more morally acceptable utilitarian responses to moral dilemmas. Interestingly, men and women in P equally accepted utilitarian resolutions of moral dilemmas, whereas in C women were less prone than men to accept utilitarian responses. We conclude that professional daily life experience of P, in an operational environment, affects moral judgment and mitigates gender predisposition towards moral dilemmas.

Mental imagery skills predict the ability in performing environmental directional judgements.

Mental imagery plays a crucial role in several cognitive processes, including human navigation. According to the Kosslyn's Model, mental imagery is subserved by three components: generation, inspection and transformation. The role of transformation, where by individuals recognise, from a different perspective, a place they have already visited, is no longer a matter of debate. However, the role of the other two components when recalling a map from different perspectives, has never been fully investigated. In the present study, we enrolled forty-nine college students and asked them to learn a schematic map and to provide directional judgements aligned or counter-aligned compared to the learnt map orientation. Their mental imagery generation, inspection and transformation skills were also investigated. Results demonstrated that all three visual mental imagery components negatively correlate with errors in providing directional judgements. Specifically, generation assumes a role in aligned directional judgements, while inspection and transformation predict the capability to provide counter-aligned directional judgements. Although all mental imagery components play a role in mentally recalling a map, only the proficiency in inspection and mental rotation can predict the accuracy in changing perspective.

Effects of Breathing and Apnoea during Sustained Inflations in Resuscitation of Preterm Infants.

BACKGROUND: A sustained inflation (SI) at birth in preterm babies may be ineffective unless the infants breathe. Gain in lung volume is associated with breathing during delivery room non-invasive management. OBJECTIVE: To describe the breathing patterns of preterm infants during an SI and correlate to a calculated gain in lung volume. METHODS: Retrospective observational study. Data collected from a respiratory function monitor during SI (25 cmH2O for 15 s then PEEP at 5 cmH2O) through a face mask in preterm infants (gestational age [GA] ≤31 weeks). Spontaneous breaths, inspiratory time (TI), inspiratory/expiratory tidal volume (Vti/Vte), and gain in lung volume were determined. RESULTS: 30 SIs in 20 infants (mean GA 27 weeks; birth weight 825 g) were analysed and stratified in 2 groups according to spontaneous breathing: SIs without spontaneous breaths (apnoea: n = 11) and SIs with spontaneous breaths (breathing: n = 19). Mean GA was lower in the apnoea group versus the breathing group (25 vs. 27+5 weeks; p = 0.01). Mean birth weight was lower in the apnoea group versus the breathing group (683 vs. 860 g; p = ns). In the breathing group, the mean number of spontaneous breaths was 4 with a mean TI of 0.52 min, the mean Vti/kg was 5.9 mL/kg, and the mean Vte was 2.7 mL/kg. The calculated mean gain in lung volume was 7.5 mL/kg in the apnoea group and 17.8 mL/kg in the breathing group (p = 0.039). CONCLUSIONS: Actively breathing infants during an SI at birth showed a gain in lung volume higher than apnoeic infants. Spontaneous breathing during SI seems to be related to GA.

Persistence of Gender Related-Effects on Visuo-Spatial and Verbal Working Memory in Right Brain-Damaged Patients.

The aim of the present study was to verify if gender differences in verbal and visuo-spatial working memory would persist following right cerebral lesions. To pursue our aim we investigated a large sample (n. 346) of right brain-damaged patients and healthy participants (n. 272) for the presence of gender effects in performing Corsi and Digit Test. We also assessed a subgroup of patients (n. 109) for the nature (active vs. passive) of working memory tasks. We tested working memory (WM) administering the Corsi Test (CBT) and the Digit Span (DS) using two different versions: forward (fCBT and fDS), subjects were required to repeat stimuli in the same order that they were presented; and backward (bCBT and bDS), subjects were required to repeat stimuli in the opposite order of presentation. In this way, passive storage and active processing of working memory were assessed. Our results showed the persistence of gender-related effects in spite of the presence of right brain lesions. We found that men outperformed women both in CBT and DS, regardless of active and passive processing of verbal and visuo-spatial stimuli. The presence of visuo-spatial disorders (i.e., hemineglect) can affect the performance on Corsi Test. In our sample, men and women were equally affected by hemineglect, therefore it did not mask the gender effect. Generally speaking, the persistence of the men's superiority in visuo-spatial tasks may be interpreted as a protective factor, at least for men, within other life factors such as level of education or kind of profession before retirement.