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bioRxiv2018

High-sensitivity c-reactive protein and total and saturated fat intake in adolescent students: a longitudinal study

ObjectiveThe present study aimed to assess the relationship between hs-CRP concentrations and total and saturated fat intake in adolescents after a year of follow-up.\n\nMethodsA longitudinal study carried out in the years 2014 and 2015 evaluated 408 adolescents from the municipal and state public schools of Joao Pessoa, Paraiba, between 10 and 14 years of age, who participated in the Longitudinal Study on Sedentary Behavior, Physical Activity, Eating Habits and Adolescent Health (LONCAAFS). Data were obtained on sociodemographic data, anthropometric nutritional status, physical activity and hs-CRP concentration. The consumption of total and saturated fats was evaluated from the 24 hour recall.\n\nResultsThe associations between concentrations of hs-CRP and total and saturated fat intake were performed by linear regression considering panel data, individual fixed effect, balanced bank, stratified by sex and BMI. The mean values of the hs-CRP variable were significantly different between the analyzed years (p = 0.024). The percentage of total and saturated fat consumption is within the recommended level in both years, with no significant difference (p> 0.05). No statistically significant associations were found between hs-CRP and total fat consumption ({beta} = -0.19p = 0.582) and saturated fat ({beta} = 0.20, p = 0.282).\n\nConclusionThe study did not present significant evidence on the relationship between the concentrations of hs-CRP and the consumption of total and saturated fats, as one year of follow-up may not have promoted evident changes in the levels of hs-CRP in adolescents.

epidemiology↗

bioRxiv2018

Exploring trend and barriers of antenatal care utilization using data mining: evidence from EDHS of 2000 to 2016

BackgroundThe healthcare industry is paying attention to pregnancy and Antenatal care (ANC) for mothers. Thus, the presented study aimed at exploring the trend and identifying the barrier for ANC utilization of mothers in Ethiopia. Data mining is a field of big data science used to discover patterns and knowledge from big data.\n\nMethodsAll EDHS datasets from 2000 to 2016 were used for this study. The pooled cross-sectional study was conducted using the knowledge discovery process having steps; selection, cleaning, integration, transformation, and data mining algorithms. These algorithms are; Classification, clustering, association rules, and attribute ranking with pattern prediction.\n\nResultsThe proportion of ANC utilization was 27.6%, 28.2%, 34.5%, and 62.9% in 2000, 2005, 2011, and 2016 respectively. The pooled data; contained 28,631 mothers which were included in the study. Of these, more than half (56.09%) of them were not utilizing ANC during a pregnancy. Pregnancy complication, educational status of mothers and husbands, mothers residence, economic status, and media exposure had an association with ANC utilization having a confidence level of 95% and above.\n\nConclusionANC utilization in Ethiopia was increased significantly from 27.6%in 2000 to 62.9% in 2016. Despite this increment, the pooled proportion of ANC utilization is still low. The barriers to this low utilization were; Pregnancy complication, poor education of mothers and their husbands, living in rural, poor economic status, and media exposure. This study will recommend; firstly, pregnant mothers have to attend ANC service even though she had no pregnancy complication. Secondly, Education and poverty reduction are key strategic area to be addressed in improving womens awareness towards ANC during a pregnancy. Thirdly, Expansion of infrastructure among the rural communities having good media coverage needs to be prioritized to improve ANC service utilization.

epidemiology↗

bioRxiv2018

Achieving the Endgame: Integrated NTD Case Searches

Trachoma and Guinea Worm Disease (GWD) are neglected tropical diseases (NTDs) slated for elimination as a public health problem and eradication respectively by the World Health Organization. As these programs wind down, uncovering the last remaining cases becomes an urgent priority. In 2010, The Ghana Health Service, along with The Carter Center, Sightsavers, and other partners, conducted integrated case search for cases of both GWD and the last stage of trachoma disease, trachomatous trichiasis (TT), as well as providing treatment for trachoma to meet elimination and eradication targets. House to house case search for both diseases was conducted and two case management strategies were explored: a centralized referral to services method and a Point of Care (POC) delivery method. 835 suspected TT cases were discovered in the centralized method, of which 554 accepted surgery. 482 suspected TT cases were discovered in the POC method and all TT cases accepted surgery in the POC searches. The cost per TT case examined was lower in the POC searches compared to the centralized searches ($19.97 in the POC searches and $20.85 in the centralized searches). Both strategies resulted in high surgical uptake for TT surgery, with average uptakes of 72.4% and 83.9% for the centralized and POC searches respectively. We present here that house to house case search offering services at POC are feasible and a potential tool for elimination and eradication programs nearing their end.\n\nAuthor SummaryTrachoma and Guinea Worm Disease (GWD) are neglected tropical diseases (NTDs) slated for elimination as a public health problem and eradication respectively by the World Health Organization. As these programs wind down, uncovering the last remaining cases becomes an urgent priority in order to confirm that eradiation/elimination targets have been reached. Active case searches are one method of finding these last vestiges of disease. Searches for that look for multiple diseases are referred to as integrated searches. We piloted here integrated case searches for GWD and Trachoma with two case management strategies, a referral approach to a central location, and point of care approach (POC). POC approaches can difficult to implement in low resource settings because they require extensive personnel, financial, and logistical, support. However, POC approaches remove one of the biggest barriers to treatment, time spent traveling to a health center, and thus can improve treatment uptake. We found here that integrated active cases searches with a POC case management approach can be implemented in a low resource setting; and improve acceptance and uptake of trachoma examination and trichiasis surgery respectively without costing much more than the referral case management approach.

epidemiology↗

bioRxiv2018

The effect of assortative mixing on stability of low helminth transmission levels and on the impact of mass drug administration: model explorations for onchocerciasis

BackgroundStable low pre-control prevalences of helminth infection are not uncommon in field settings, yet it is poorly understood how such low levels can be sustained, thereby challenging efforts to model them. Disentangling possible facilitating mechanisms is important, since these may differently affect intervention impact. Here we explore the role of assortative (i.e. non-homogenous) mixing and exposure heterogeneity in helminth transmission, using onchocerciasis as an example.\n\nMethodology/Principal FindingsWe extended the established individual-based model ONCHOSIM to allow for assortative mixing, assuming that individuals who are relatively more exposed to fly bites are more connected to each other than other individuals in the population as a result of differential exposure to a sub-population of blackflies. We used the model to investigate how transmission stability, equilibrium microfilariae (mf) prevalence and intensity, and impact of mass drug administration depend on the assumed degree of assortative mixing and exposure heterogeneity, for a typical rural population of about 400 individuals. The model clearly demonstrated that with homogeneous mixing and moderate levels of exposure heterogeneity, onchocerciasis could not be sustained below 35% mf prevalence. In contrast, assortative mixing stabilised onchocerciasis prevalence at levels as low as 8% mf prevalence. Increasing levels of assortative mixing significantly reduced the probability of interrupting transmission, given the same duration and coverage of mass drug administration.\n\nConclusions/SignificanceAssortative mixing patterns are an important factor to explain stable low prevalence situations and are highly relevant for prospects of elimination. Their effect on the pre-control distribution of mf intensities in human populations is only detectable in settings with mf prevalences <30%, where high skin mf density in mf-positive people may be an indication of assortative mixing. Local spatial variation in larval infection intensity in the blackfly intermediate host may also be an indicator of assortative mixing.\n\nAuthor summaryMost mathematical models for parasitic worm infections predict that at low prevalences transmission will fade out spontaneously because of the low mating probability of male and female worms. However, sustained low prevalence situations do exist in reality. Low prevalence areas have become of particular interest now that several worm infections are being targeted for elimination and the question arises whether transmission in such areas is driven locally and should be targeted with interventions. We hypothesise that an explanation for the existence of low prevalence areas is assortative mixing, which is the preferential mixing of high-risk groups among themselves and which has been shown to play an important role in transmission of other infectious diseases. For onchocerciasis, assortative mixing would mean that transmission is sustained by a sub-group of people and a connected sub-population of the blackfly intermediate host that mix preferentially with each other. Using a mathematical model, we study how assortative mixing allows for sustained low prevalences and show that it decreases the probability of interrupting transmission by means of mass drug administration. We further identify data sources that may be used to quantify the degree of assortative mixing in field settings.

epidemiology↗

bioRxiv2018

Storage length and temperature influence infectivity and spore yield of two common Daphnia parasites

Daphnia and their parasites have emerged as a model system for understanding the ecology and evolution of infectious diseases. Two of the most commonly studied Daphnia parasites are the bacterium Pasteuria ramosa and the fungus Metschnikowia bicuspidata. In addition to being the focus of numerous field studies, these two parasites have been used in many laboratory experiments. However, there is little information in the scientific literature about how the conditions under which these parasites are stored influence the infectivity and yield of transmission stages (\"spores\"). This is problematic because such information is critical for experiment design and data interpretation.\n\nWe tested the influence of storage length (eight treatments ranging from 1 day to 1 year) and temperature (-20{degrees}C (freezer) vs. 4{degrees}C (refrigerator)) on spore infectivity and yield. We found that Pasteuria spores survived well at both -20{degrees}C and 4{degrees}C, and remained infective even after storage for one year. However, Pasteuria spore yields dropped over time, particularly at 4{degrees}C. In contrast, Metschnikowia spores were killed within days at -20{degrees}C. At 4{degrees}C, Metschnikowia infectivity declined steadily over a period of two months and, by four months, spores were no longer infective. Spore yield from Metschnikowia-infected hosts was not significantly impacted by storage length, but trended downwards.\n\nScientists working with Pasteuria should be aware that spore yield declines during storage, particularly in the refrigerator. Scientists working with Metschnikowia should be aware that it is killed by freezer storage and that, even if it is stored in the refrigerator, infectivity declines within a few months. These results might have implications for parasite distributions in the field; for example, the high sensitivity of Metschnikowia to freezing might help explain why it tends to be more common in deep lakes than in ponds or rock pools.

epidemiology↗

bioRxiv2018

Robustness of local control strategies under modelling uncertainties: the 2004 avian infuenza H5N1 outbreak in Thailand

The Highly Pathogenic Avian Influenza (HPAI) subtype H5N1 virus persists in many countries and has been circulating in poultry, wild birds. In addition, the virus has emerged in other species and frequent zoonotic spillover events indicate that there remains a significant risk to human health. It is crucial to understand the dynamics of the disease in the poultry industry to develop a more comprehensive knowledge of the risks of transmission and to establish a better distribution of resources when implementing control. In this paper, we develop a set of mathematical models that simulate the spread of HPAI H5N1 in the poultry industry in Thailand, utilising data from the 2004 epidemic. The model that incorporates the intensity of duck farming when assessing transmision risk provides the best fit to the spatiotemporal characteristics of the observed outbreak, implying that intensive duck farming drives transmission of HPAI in Thailand. We also extend our models using a sequential model fitting approach to explore the ability of the models to be used in \"real time\" during novel disease outbreaks. We conclude that, whilst predictions of epidemic size are estimated poorly in the early stages of disease outbreaks, the model accurately predicts the preferred control policy that should be deployed to minimise the impact of the disease.

epidemiology↗

bioRxiv2018

Critical transitions in malaria transmission models are consistently generated by superinfection

The history of infectious disease modelling essentially begins with the papers by Ross on malaria [1-5]. These models assume that the dynamics of malaria can most simply be characterized by two equations that describe the prevalence of malaria in the human and mosquito hosts. This structure has formed the central core of models for malaria and most other vector-borne diseases for the last century with occasional additions acknowledging important aetiological details. We partially add to this tradition by describing a malaria model that provides for vital dynamics in the vector and the possibility of super-infection in the human host; reinfection of asymptomatic hosts before they have cleared a prior infection. These key features of malaria aetiology create the potential for break points in the prevalence of infected hosts, sudden transitions that seem to characterize malarias response to control in different locations. We show that this potential for critical transitions is a general and underappreciated feature of any model for vector borne diseases with incomplete immunity and asymptomatic patients, including the canonical Ross-McDonald model. Ignoring these details of the hosts immune response to infection can potentially lead to serious misunderstanding in the interpretation of malaria distribution patterns and the design of control schemes for other vector-borne diseases.

epidemiology↗

bioRxiv2018

Human Immunodeficiency Virus Status in Malnourished Children seen at Lagos.

IntroductionHuman immunodeficiency virus and protein energy malnutrition are still prevalent in Nigeria and the occurrence of the two conditions together confers a poor prognosis. The aim of this study was to determine the current categories of malnutrition amongst under 5 children in Lagos, document their HIV status and determine any peculiarities in the clinical features, haematological and some biochemical profile in these children.\n\nMethodsThe study was a prospective crossectional study conducted at the Paediatric department of the Lagos University Teaching Hospital and the Massey Street Childrens Hospital over a 6 month period. All the subjects had anthropometry, HIV testing, full blood count and serum proteins done. The factors associated with HIV status were determined with the logistic regression analysis.\n\nResultsTwo hundred and fourteen (214) malnourished children [≤]5 years were recruited into the study and 25(11.7%) were HIV positive. One hundred and five (49.1%) of the participants had moderate malnutrition while 25.2% had severe forms of malnutrition. Fever, cough and diarrhea were the commonest symptoms. Severe wasting, oral thrush, dermatoses and splenomegaly were seen more commonly in the HIV positive subjects. The haematological indices were comparable in the two groups, however, the total protein was significantly higher in the HIV positive subjects compared to the negative group (p=0.042). Multivariate analysis showed that the total protein (p=0.001) and platelet count (p=0.016) could significantly predict the occurrence of HIV in the malnourished children\n\nConclusionThe presence of severe wasting, oral thrush, diarrhea, splenomegaly, thrombocytopenia and high total proteins in malnourished children should heighten the suspicion of possible underlying associated HIV infection. This study reinforces the recommendation by the World Health Organisation (WHO) that all malnourished children should have mandatory HIV screening.

epidemiology↗

bioRxiv2018

Bearing the brunt: Mongolian khulan (Equus hemionus hemionus) are exposed to multiple influenza A strains

The majority of influenza A virus strains are hosted in nature by several Anseriformes and Charadriformes birds. A minority of strains have been able to cross species boundaries and establish themselves in novel non-avian hosts. Influenza viruses of horses, donkeys, and mules represent successful cases of avian to mammal influenza virus adaptation. Mongolia has over 3 million domestic horses and is home to two wild equids, the Asiatic wild ass (Equus hemionus hemionus), and Przewalski horse (Equus ferus przewalskii). Domestic and wild equids are sympatric across most of their range in Mongolia. Epizootic influenza A virus outbreaks among Mongolian domestic horses have been frequently recorded. However, the exposure, circulation and relation to domestic horse influenza A virus outbreaks among wild equids is unknown. We evaluated serum samples of Asiatic wild asses in Mongolia for antibodies against influenza A viruses, using a serological assay. We detected antibodies against hemagglutinin (H) H1, H3, H5, H7, H8 and H10 influenza A viruses. Asiatic wild asses may represent a previously unidentified influenza A virus reservoir in an ecosystem shared with populations of domestic horses in which influenza strains circulate.

epidemiology↗

bioRxiv2018

Antiretroviral Adverse Drug Reactions Pharmacovigilance in Harare City, Zimbabwe, 2017

IntroductionKey to pharmacovigilance is spontaneously reporting all Adverse Drug Reactions (ADR) during post-market surveillance. This facilitates identification and evaluation of previously unreported ADRs, acknowledging the trade-off between benefits and potential harm of medications. Only 41% ADRs documented in Harare city clinical records for January to December 2016 were reported to Medicines Control Authority of Zimbabwe (MCAZ). We investigated reasons contributing to underreporting of ADRs in Harare city.\n\nMethodsA descriptive cross-sectional study and the updated Centers for Disease Control (CDC) guided surveillance evaluation was conducted. Two hospitals were purposively included. Seventeen health facilities and 52 health workers were randomly selected. Interviewer-administered questionnaires, key informant interviews and WHO pharmacovigilance checklists were used to collect data. Likert scales were applied to draw inferences and Epi info 7 used to generate frequencies and proportions.\n\nResultsOf the 52 participants, 32 (61.5%) distinguished the ADR defining criteria. Twenty-nine (55.8%) knew systems purpose whilst 28 (53.8%) knew the reporting process. Knowledge scored average on the 5-point-Likert scale. Thirty-eight (73.1%) participants identified ADRs following client complaints and nine (1.3%) enquired clients medication response. Forty-six (88.5%) cited non-feedback from MCAZ for underreporting. Inadequate ADR identification skills were cited by 21 (40.4%) participants. Reporting forms were available in five (26.3%) facilities and reports were generated from hospitals only. Forty-two (90.6%) clinicians made therapeutic decisions from ADRs. Averaged usefulness score was 4, on the 5-point-Likert scale. All 642 generated signals were committed to Vigiflow by MCAZ, reflecting a case detection rate of 4/ 100 000. Data quality was 0.75-1.0 (WHO) and all reports were causally assessed.\n\nConclusionThe pharmacovigilance system was useful, simple, and acceptable despite being unstable, not representative and not sensitive. It was threatened by suboptimal health worker knowledge, weak detection strategies and referral policy preventing ADR identification by person place and time. Revisiting local policy, advocacy, communication and health worker orientation might improve pharmacovigilance performance in Harare city.

epidemiology↗

bioRxiv2018

Genetic heterogeneity in Anopheles darlingi related to biting behavior in western Amazon

In the Amazon Basin, Anopheles (Nyssorhynchus) darlingi is the most aggressive and effective malaria vector. In endemic areas, behavioral aspects of anopheline species such as host preference, biting time and resting location after a blood meal have a key impact on malaria transmission dynamics and transmission control strategies. An. darlingi present a variety in behavior throughout its broad distribution including blood feeding related. To investigate the genetic basis of its biting behaviors, host-seeking An. darlingi were collected in two settlements (Granada and Remansinho) in Acre, Brazil. Mosquitoes were classified by captured location (indoors or outdoors) and time (dusk or dawn). Genome-wide SNPs were used to assess the degree of genetic diversity and structure in these groups. There was evidence of genetic component of biting behavior regarding both location and time in this species. This study supports that An. darlingi blood-feeding behavior has a genetic component. Additional ecological and genomic studies may help to understand the genetic basis of mosquito behavior and address appropriate surveillance and vector control.\n\nAuthor SummaryMalaria is a disease caused by parasite of the genus Plasmodium and is transmitted by mosquitoes of the genus Anopheles. In the Amazon Basin, the main malaria vector is Anopheles darlingi, which is present in high densities in this region. Egg development requires that females of this mosquito seek hosts for blood meals. Anopheles females blood feeding may occur indoor or outdoor the houses and typically from the sunset to dawn. Anopheles darlingi in particular present great variability regarding its behaviour, presenting variety of peak biting times and patterns. This work shows that there is a genetic component that partially explains these two behaviors: location of the blood meal (inside or outside the houses) and time of feeding. Single nucleotide polymorphisms (SNPs) scattered throughout the genome of Anopheles darlingi showed genetic diversity and structure in these groups. A comprehensive understanding of the genetic basis for mosquito behaviour may support innovative vector surveillance and control strategies.

epidemiology↗

bioRxiv2018

Impact of Premorbid Infection on Onset and Disease Activity of Rheumatoid Arthritis

ObjectiveInfections have been implicated in rheumatoid arthritis (RA) development. However, the impact of premorbid infection on initiation and perpetuation of RA has not been well elucidated. Thus, we sought to conduct a large scale on-site survey to study whether premorbid infection may trigger RA and influence status of the disease.\n\nMethodsPremorbid infectious events were collected in cohort of 902 RA patients from December 2015 to June 2016. Type of infections prior to RA onset and its possible effects on disease status were analyzed.\n\nResultThree hundred and thirty-four out of 902 patients (37.03%) experienced infections within one month preceding RA onset. The most frequent infections were respiratory (16.08%), intestinal (11.09%) and urinary tract (9.87%) infection, respectively. The infection was associated with increased disease activity. Early onset was found in patients with urinary infection. High disease activity risk was increased in patients who pre-exposure to urinary infection (OR=3.813, 95%CI=1.717-12.418) and upper respiratory infection (OR=2.475, 95%CI= 0.971-6.312).\n\nConclusionPre-exposure infections are associated with development of RA. Severe disease status of RA and persistent of active disease status are related to preceding infections.

epidemiology↗

bioRxiv2018

Anopheles Mosquitoes May Drive Invasion and Transmission of Mayaro Virus across Geographically Diverse Regions

The Togavirus (Alphavirus) Mayaro virus (MAYV) was initially described in 1954 from Mayaro County (Trinidad) and has been responsible for outbreaks in South America and the Caribbean. Imported MAYV cases are on the rise, leading to invasion concerns similar to Chikungunya and Zika viruses. Little is known about the range of mosquito species that are competent MAYV vectors. We tested vector competence of 2 MAYV genotypes for six mosquito species (Aedes aegypti, Anopheles gambiae, An. stephensi, An. quadrimaculatus, An. freeborni, Culex quinquefasciatus). Ae. aegypti and Cx. quinquefasciatus were poor MAYV vectors, and either were poorly infected or poorly transmitted. In contrast, all Anopheles species were able to transmit MAYV, and 3 of the 4 species transmitted both genotypes. The Anopheles species tested are divergent and native to widely separated geographic regions, suggesting that Anopheles may be important in the invasion and spread of MAYV across diverse regions of the world.

epidemiology↗

bioRxiv2018

CAN NEUROPATHIC PAIN PREDICT RESPONSE TO ARTHROPLASTY IN KNEE OSTEOARTHRITIS? A PROSPECTIVE OBSERVATIONAL COHORT STUDY.

A significant proportion of patients with knee osteoarthritis (OA) continue to have severe ongoing pain following knee replacement surgery. Central sensitization and features suggestive of neuropathic pain before surgery may result in a poor outcome post-operatively. In this prospective observational study of patients undergoing primary knee arthroplasty (n=120), the modified PainDETECT score was used to divide patients, with primary knee OA, into nociceptive (<13), unclear (13-18) and neuropathic -like pain (>18) groups pre-operatively. Response to surgery was compared between groups using the Oxford Knee Score (OKS) and the presence of moderate to severe long-term pain 12 months after arthroplasty. The analyses were replicated in a larger independent cohort study (n=404). 120 patients were recruited to the main study cohort: 63 (52%) nociceptive pain; 32 (27%) unclear pain; 25 (21%) neuropathic-like pain. Patients with neuropathic-like pain had significantly worse OKS pre and post-operatively, compared to the nociceptive pain group, independent of age, sex and BMI. At 12-months post-operatively the mean OKS was 4 points lower in the neuropathic-like group compared with the nociceptive group in the study cohort (non-significant); with a difference of 5 points in the replication cohort (p<0.001). Moderate to severe long-term pain after arthroplasty at 12-months was present in 50% of the neuropathic-like pain group versus 24% in the nociceptive pain group, in the replication cohort (p<0.001). Neuropathic pain is common and targeted therapy pre, peri and post-operatively may improve treatment response.

epidemiology↗

bioRxiv2018

MVSE: an R-package that estimates a climate-driven mosquito-borne viral suitability index.

BackgroundViruses such as dengue, Zika, yellow fever and chikungunya depend on mosquitoes for transmission. Their epidemics typically present periodic patterns, linked to the underlying mosquito population dynamics, which are known to be driven by natural climate fluctuations. Understanding how climate dictates the timing and potential of viral transmission is essential for preparedness of public health systems and design of control strategies.\n\nResultsWe developed the Mosquito-borne Viral Suitability Estimator (MVSE) software package for the R programming environment. The package estimates a suitability index based on a climate-driven mathematical expression for the basic reproductive number (R0) of a well established mathematical model for the transmission dynamics of mosquito-borne viruses. By accounting for local humidity and temperature, as well as viral, vector and human priors, suitability can be estimated for specific host and viral species, as well as different regions of the globe.\n\nConclusionsHere, we describe the background theory and biological interpretation of the new suitability index, as well as the implementation, basic functionality, research and educational potentials of the MVSE R-package. The package is freely available under the GPL 3.0 license.

epidemiology↗

bioRxiv2018

The Association between Cigarette Affordability and Consumption

ObjectivesTo calculate cigarette affordability for 78 countries worldwide from 2001 to 2014 using the Relative Income Price (RIP) ratio defined as the percentage of per capita GDP required to purchase 100 packs of cigarettes using the lowest price from Economist Intelligence Unit (EIU) database, examine the association between cigarette affordability and cigarette consumption, and calculate the affordability elasticity of demand.\n\nDesign and MethodsRIP (2001-2014) was calculated for 16 low-income economies, 19 lower middle-income economies, 13 upper middle-income economies, and 30 high-income economies. Ordinary least square regressions were used to analyze the association between cigarette affordability and consumption.\n\nResults and ConclusionsPer capita consumption continued to rise in low-income countries and decreased slightly in lower middle-income countries as the RIP of cigarette consistently declined in low- and lower middle-income economies from 2001 to 2014. The real cigarette prices continued to decline in low- and lower middle-income countries and continued to rise in upper middle- and high-income countries. Though cigarettes were more expensive in HICs than were in LMICs, cigarettes were more affordable in HICs than were in LMICs. The regression results show a 10% increase in the RIP of cigarettes led to a 2% decrease in per capita consumption. The affordability elasticity of demand differed significantly between HICs and LMICs. However, the effect of cigarette affordability on consumption has not changed over time. To control the smoking epidemic, low- and lower middle-income countries should further increase cigarette prices. The rate of price increase should exceed the rate of economic growth and outpace the inflation rate to make cigarettes less affordable and thereby reducing tobacco use.

epidemiology↗

bioRxiv2018

Prevalence and determinants of smoking status among university students: Artvin Coruh University sample

Background and aimWhile smoking prevalence has decreased in many developed countries, in others it is still an increasing risk factor for public health, especially among young adults. In this study we aimed to find the factors affecting university students smoking status.\n\nMethodsThis cross-sectional study was conducted between March and June 2017 with a simple random sampling method. A self-administered questionnaire was used to collect information on sociodemographic characteristics, cigarette smoking status, and the related risk factors. Univariate analysis and multivariate logistic regression analysis with the Backward:LR test were performed.\n\nResultsOut of 2723 students, 2505 students data were available and suitable for analysis. Mean participant age was 20.9{+/-}2.5, with female dominance (58.9%). Students studying in two-year degree departments comprised 45.6% of the study population, and the remaining 54.4% of the students were in 4-year degree departments. In terms of parental smoking habits, 36.1% reported a smoker father, while that rate was 10.3% for mothers and 15.0% for siblings. Current smokers represented 27.9% of the group: 46% among males and 15.3% among females. Mean age for beginning smoking was 16.34{+/-}2.72, 15.65{+/-}2.67 for males, 16.34{+/-}2.72 for females (p<0.05). Mean Fagerstromtest score was 4.43{+/-}1.82, and female students had lower test scores than males (p<0.05). After controlling for potential confounders in multivariate analysis, it was seen that five factors were positively associated with current smoking (p<0.05): male gender (OR:3.43; 95%, CI:2.75-4.28), studying in two-year programs (OR: 1.74; 95% CI: 1.39-2.18), having at least one close family member who is a smoker (OR:1.63; 95% CI:1.31-2.04), having close friends who are all smokers (OR:1.81; 95% CI: 1.40-2.33), and alcohol consumption (OR:4.39; 95% CI: 3.51-5.49).\n\nConclusionOur study showed a higher smoking rate among our study population, both compared to similar nationalstudies and the countrys overall smoking rate. Underlying factors should be evaluated via qualitative studies and preventive strategies should be implemented accordingly.

epidemiology↗

bioRxiv2018

An Advancing Front of Old Age Human Survival

Old age mortality decline has driven recent increases in lifespans, but there is no agreement about trends in the age-pattern of old deaths. Some hypotheses argue that old-age deaths should have become compressed at high ages, others that old-age deaths should have become more dispersed with age, and yet others are consistent with little change in dispersion. However, direct analyses of old-age deaths presents unusual challenges: death rates at the oldest ages are always noisy; published life tables must assume an asymptotic age pattern of deaths; and the definition of \"old age\" changes as lives lengthen. Here we use robust percentile-based methods to overcome these challenges and show, for 5 decades in 20 developed countries, that old-age survival follows an advancing front, like a traveling wave. The front lies between the 25th and 90th percentiles of old-age deaths, advancing with nearly constant long-term shape but annual fluctuations in speed. The existence of this front leads to several predictions that we verify, e.g., that advances in life expectancy at age 65 are highly correlated with the advance of the 25th percentile, but not with distances between higher percentiles. Our unexpected result has implications for biological hypotheses about human aging, and for future mortality change.

epidemiology↗