A Bayesian approach to fuzzy hypotheses testing for the estimation of optimal age for vaccination against measles

Fuzzy Bayesian tests were performed to evaluate whether the mother’s seroprevalence and children’s seroconversion to measles vaccine could be considered as “high” or “low”. The results of the tests were aggregated into a fuzzy rule-based model structure, which would allow an expert to influence the model results. The linguistic model was developed considering four input variables. As the model output, we obtain the recommended age-specific vaccine coverage. The inputs of the fuzzy rules are fuzzy sets and the outputs are constant functions, performing the simplest Takagi–Sugeno–Kang model. This fuzzy approach is compared to a classical one, where the classical Bayes test was performed. Although the fuzzy and classical performances were similar, the fuzzy approach was more detailed and revealed important differences. In addition to taking into account subjective information in the form of fuzzy hypotheses it can be intuitively grasped by the decision maker.     

Neck/shoulder and low-back disorders in the forestry industry: relationship to work tasks and perceived psychosocial job stress

In a national cross-sectional study, the prevalence of neck/shoulder and low-back disorders and their relationship to work tasks and perceived psychosocial job stress was studied among forestry employees. The data were collected by occupational health service staff using Karasek's demand/control questionnaire for the psychosocial measures and the Standardized Nordic questionnaire for the analysis of musculoskeletal disorders. Based on data about past and present work tasks, the study population was classified into three groups: 645 manual workers, 66 machine operators and 124 administrative workers. Low-back disorders were more common among the manual workers than among the administrative workers \[odds ratio (OR) = 1.98]. For the machine operators and manual workers, an increasing level of psychological demands was significantly associated with an increased prevalence of low-back disorders. The prevalence of neck/ shoulder disorders was significantly higher among the machine operators (OR = 3.37) and manual workers (OR = 2.34) than among the administrative workers. An increasing level of psychological demands combined with a decreasing level of intellectual discretion was associated with an increased prevalence of neck/shoulder disorders. Authority over decisions was not associated with musculoskeletal disorders. In conclusion, musculoskeletal disorders were associated with both physical and psychosocial work factors. The modest strength of the associations between each individual independent variable and the outcome measure shows, however, that a substantial reduction in the prevalence of musculoskeletal disorders may be difficult to achieve. Nevertheless, the study clearly suggests that in the forestry industry attention should be paid to psychosocial work factors in future organizational changes and preventive programmes.     

Effect of the helmet act for motorcyclists in Thailand

OBJECTIVES: This study investigated the effect of the helmet act for motorcyclists on increasing helmet use and reducing motorcycle-related deaths and severe injuries in Thailand. METHODS: Data were derived from a trauma registry at the Khon Kaen Regional Hospital in the northeast Thailand. Helmet use and outcome in motorcycle crashes were compared 2 years before (1994-1995) and after (1996-1997) enforcement of the helmet act. During the study period, there were 12002 injured motorcyclists including 129 death cases in the municipality of Khon Kaen Province who were brought to the regional hospital. RESULTS: After enforcement of the helmet act, helmet-wearers increased five-fold while head injuries decreased by 41.4% and deaths by 20.8%. Those who had head or neck injuries or died were less likely wearing a helmet. Compliance of helmet use was lower at night. Fatality of injured motorcyclists did not significantly decrease in the post-act period and among helmet-wearers. CONCLUSION: Enforcement of the helmet act increased helmet-wearers among motorcyclists but helmet use did not significantly reduce deaths among injured motorcyclists. Motorcyclists should be instructed to properly and consistently wear a helmet for their safety.     

Driving-while-intoxicated history as a risk marker for general aviation pilots

The Federal Aviation Administration conducts background checking for driving-while-intoxicated (DWI) convictions on all pilots. This study examined the association between DWI history and crash risk in a cohort of 335,672 general aviation pilots. These pilots were followed up from 1994 to 2000 through the aviation crash surveillance system of the National Transportation Safety Board. At baseline, 3.4% of the pilots had a DWI history. DWI history was associated with a 43% increased risk of crash involvement (adjusted relative risk: 1.43; 95% confidence interval: 1.15-1.77). The population-attributable risk fraction for DWI history was estimated as 1.4%. In addition to DWI history, male gender, older age, and inexperience were associated with significantly increased risk of crash involvement. The results of this study support DWI history as a valid risk marker for general aviation pilots. The safety benefit of background checking for DWI history needs to be further evaluated.     

Do we all face the same risk when bathing in the estuary?

With the development of coastal areas, microbial water quality is an emerging public health issue though few studies have focused on risks according to age. A survey was undertaken of faecal contamination in relation to recreational activities in the Peel Harvey estuarine system, Western Australia. Levels of exposure to contaminated water were estimated though social surveys. Follow-up was also conducted to estimate the incidence of disease associated with bathing in the estuary. Pathogen levels exceeded the guideline values recommended by the World Health Organisation (WHO) at most locations throughout the year. The social survey provided information about exposure of the population in age groups. Only 31% of the recreational users belonged to the healthy adult group upon which the WHO quantitative microbial risk assessment model is based. A correlation was established between microbial water quality and incidence of respiratory diseases for children as well as for adults. Exposure to recreational water increased the incidence of respiratory illnesses for the whole population almost by a factor 2. Behaviours which resulted in increased exposures were associated with increased incidence of illnesses were observed, particularly among children aged 11-15 yr, who exhibited the highest odd ratio (OR 4.23 [2.44-6.01], CI 95%, p=0.05). There is a need for combining epidemiology studies with risk assessment processes and complementing them with social surveys for understanding the risk of recreational activities to public health.     

Chronic exposure to volcanic environments and cancer incidence in the Azores, Portugal

Whether volcanic environments pose a risk in cancer incidence is unknown. We investigated this question in two populations, one from an area with active manifestations of volcanism (Furnas) and another from an area without volcanic activity since 3 million years ago (Santa Maria), both in Azores. Incidence data on cancer among the populations of Furnas and Santa Maria during 1991-2001 were obtained from medical records of local health centers. Age-standardized rates and relative risks were estimated. Overall incidence rates were higher in the volcanically active area when observing all cancers and both sexes combined. However, the non-volcanically active area presented higher rates of cancer of digestive, respiratory and intrathoracic organs, mainly in males, while the area with volcanic manifestations showed higher rates of cancer of lip, oral cavity and pharynx, in both sexes, and female breast. Relative risk estimates between both populations suggest a higher risk for cancer in some groups of organs in Furnas, especially of lip, oral cavity and pharynx cancer, and breast, that may be partially explained by the chronic exposure to environmental factors resulting from volcanic activity, such as hazardous gases and aerosols, much of them associated to trace metals.     

Do German drivers use their smartphones safely?—Not really!

Research in the laboratory as well as in naturalistic driving studies has shown that texting while driving seems to be the most dangerous driver distraction. However, there is still some discussion about the extent to which drivers adapt their behavior to the traffic situation. Accordingly, they might use their phones only in easy driving situations but refrain from doing so when driving becomes more demanding. For Germany, no reliable data on these topics could be found although overall smartphone use has also increased exponentially in this country. As observational studies have proven to be an effective means to gather these data, such a study was done observing 11,837 drivers in three big German cities (Braunschweig, Hannover, Berlin) during daytime. An alarmingly high rate of texting while driving was found (4.5%) as compared to other international studies. This was even more frequent than the use of handheld (2.2%) and hands-free (1.7%) phones combined. Thus, there seems to be a special problem in Germany with texting which should be further examined as this activity is highly distracting. Finally, there was some indication that drivers adapt their secondary task activities to the requirements of the driving task (e.g. somewhat less texting when moving than when stationary at a red traffic light). However, these adaptations were not very strong. Thus, drivers seem to underestimate the dangers due to distraction. This could be a starting point for countermeasures which increase this awareness of danger.     

Multitask learning and nonlinear optimal control of the COVID-19 outbreak: A geometric programming approach

We propose a multitask learning approach to learn the parameters of a compartmental discrete-time epidemic model from various data sources and use it to design optimal control strategies of human-mobility restrictions that both curb the epidemic and minimize the economic costs associated with implementing non-pharmaceutical interventions. We develop an extension of the SEIR epidemic model that captures the effects of changes in human mobility on the spread of the disease. The parameters of the model are learned using a multitask learning approach that leverages both data on the number of deaths across a set of regions, and cellphone data on individuals’ mobility patterns specific to each region. Using this model, we propose a nonlinear optimal control problem aiming to find the optimal mobility-based intervention strategy that curbs the spread of the epidemic while obeying a budget on the economic cost incurred. We also show that the solution to this nonlinear optimal control problem can be efficiently found, in polynomial time, using tools from geometric programming. Furthermore, in the absence of a straightforward mapping from human mobility data to economic costs, we propose a practical method by which a budget on economic losses incurred may be chosen to eliminate excess deaths due to over-utilization of hospital resources. Our results are demonstrated with numerical simulations using real data from the COVID-19 pandemic in the Philadelphia metropolitan area.     

Chronic exposure to biomass fuel smoke and markers of endothelial inflammation

Indoor smoke exposure may affect cardiovascular disease (CVD) risk via lung‐mediated inflammation, oxidative stress, and endothelial inflammation. We sought to explore the association between indoor smoke exposure from burning biomass fuels and a selected group of markers for endothelial inflammation. We compared serum concentrations of amyloid A protein, E‐selectin, soluble intercellular adhesion molecule 1 (ICAM‐1) and VCAM‐1, von Willebrand factor (vWF), and high‐sensitivity C‐reactive protein (hs‐CRP) in 228 biomass‐exposed vs. 228 non‐exposed participants living in Puno, Peru. Average age was 56 years (s.d. = 13), average BMI was 26.5 kg/m² (s.d. = 4.4), 48% were male, 59.4% completed high school, and 2% reported a physician diagnosis of CVD. In unadjusted analysis, serum levels of soluble ICAM‐1 (330 vs. 302 ng/ml; P < 0.001), soluble VCAM‐1 (403 vs. 362 ng/ml; P < 0.001), and E‐selectin (54.2 vs. 52.7 ng/ml; P = 0.05) were increased in biomass‐exposed vs. non‐exposed participants, respectively, whereas serum levels of vWF (1148 vs. 1311 mU/ml; P < 0.001) and hs‐CRP (2.56 vs. 3.12 mg/l; P < 0.001) were decreased, respectively. In adjusted analyses, chronic exposure to biomass fuels remained positively associated with serum levels of soluble ICAM‐1 (P = 0.03) and VCAM‐1 (P = 0.05) and E‐selectin (P = 0.05), and remained negatively associated with serum levels of vWF (P = 0.02) and hs‐CRP (P < 0.001). Daily exposure to biomass fuel smoke was associated with important differences in specific biomarkers of endothelial inflammation and may help explain accelerated atherosclerosis among those who are chronically exposed.     

Ergonomics diary

The link between occupation and musculoskeletal disorders has been focused on in numerous research projects, ranging from those simply observing the different pathological findings reported among workers performing particular tasks, down to the latest studies actually quantifying the ‘exposure’ of workers to physical and psychosocial stimuli. For some disorders and certain tissues, it has been reported that specific types of work-related exposure are associated with the development of musculoskeletal pathologies, and that the relative risks for certain types of occupational exposure can be extremely high. This has been proven in relation to tendinitis of the shoulder and hand-wrist, carpal tunnel syndrome, as well as several localized aspecific musculoskeletal symptoms, such as pain. For other pathologies, the studies reported contradictory results. This is the case for lateral epicondylitis and cervical radiculopathy.