Epidemiology and Public Health

Epidemiology and Public Health

  • Garumma Tolu Feyissa added an answer:
    Can a randomized controlled trial (RCT) be retrospective?
    Recently I came across an article titled "A retrospective randomized study of asthma control in the US: results of the CHARIOT study." I couldn't get the full article, but I have some doubts that an RCT can be retrospective?
    Garumma Tolu Feyissa

    Thank you for the nice discussion. If either randomization or a control group is missing from a study, it may be quasi-experimental study design. Can a retrospective review of RCTs be considered as quasi-experimental study?

  • Suhail A. Doi added an answer:
    When undertaking a meta-analysis, which effect is most appropriate: fixed effect or random effect?

    Meta-analyses, epidemiology, public health

    Suhail A. Doi

    Dr Kumar, thanks for your response, A weighting sensitivity plot is used to assess to what extent the effect model (fixed or random) may influence the results. This is meta-analysis dependent and tells us nothing whatsoever about which estimator has the lesser variance and MSE and that is actually what is of interest. A simple simulation will demonstrate that the fixed effect estimator always has a lesser MSE and therefore performs  better and all the theories above about choice of estimator are indeed wrong. Yes, fixed effect estimators are biased, but since we only do a meta-analysis once, the lower MSE estimator will be closest to to reality irrespective of bias. The only situation where the MSE of random and fixed effect estimators come together (because of bias in the latter) is when there are hundreds of studies in the meta-analysis - really unrealistic situation. Keep in mind that if you do decide to use the fixed effect estimator for heterogenous studies, only the IVhet approach is valid as this has a corrected variance (corrected for overdispersion).

  • Seyed Ramin Radfar added an answer:
    Are there any suggestions to Design Patient Education Material with Holistic Approach for HIV-AIDS ?

    Dear all,

    kindly give your valuable suggestion as i am going to design patient Education Material with Holistic Approach. for HIV-AIDS Patients.

    Thanks in Advance

    Seyed Ramin Radfar

    Our experiences shows that more inter active is more effective .Side effects of ART and how to cope with it is very important for patients' adherence, other important based on our study is family stigma that should be targeted by IEC approaches.

  • Rodney P Jones added an answer:
    Is the UK in the middle of an unrecognised infectious outbreak?
    In 1993, 1996, 2002, 2007 and 2012 the UK saw an unexpected and unexplained increase in deaths, emergency medical admissions, emergency department attendances and GP referrals. These events appear to initiate earlier in Scotland and involve infectious-like spread for the increase in morbidity and mortality. It has been suggested that increases in the level active cytomegalovirus infection may be implicated. Further papers investigating this phenomena are available at www.hcaf.biz. Any thoughts, comments or suggestions would be useful.
    Rodney P Jones

    I have subsequently published additional studies demonstrating small-area spread of this unknown agent.

    Easiest option is to go to 


    and download some of the more recent publications.

  • Liza Seubert added an answer:
    Does anyone have publications on enhancing communication between consumers and community pharmacy staff for over the counter requests?

    I am conducting a systematic review of intervention studies and am interested in finding all relevant publications. If you would like more information, the review protocol is registered on Prospero:


    I can be contacted via this ResearchGate portal 

    Liza Seubert

    Dear Ibrahim,

    Thank you for spending the time to respond to my question - it adds to the completeness of the review.

    Kind regards,


  • Ashwani Kumar Tiwari added an answer:
    How important is drinking water quality to good health?
    The age old drinking water quality vs. quantity debate rages on, even as sanitation and hygiene are being promoted intensively.
    Ashwani Kumar Tiwari

    Dear Mark,

    Water often consist of major chemical elements Ca2+, Mg2+, Na+, K+, Cl-, F- NO3- and SO42-. These chemical elements play very important role in human health. The concentration of major chemical elements under desirable limit is good for health but increase the concentration of the element above the desirable limit may cause adverse effects on human health. Major problems being faced by the World  population are due to the presence of excess fluoride, sulphate, chloride, nitrate, total hardness  sodium and same metals in water.


  • Dr. Senthilvel Vasudevan added an answer:
    Are there any studies linking benzo(a)pyrene levels and type 2 diabetes?

    Does anybody know of epidemiological studies relating exposure to benzo(a)pyrene or levels of other PAH measured in the air and type 2 diabetes? I only found studies using urinary metabolites as markers of exposure.

    Dr. Senthilvel Vasudevan

    Dear Angel, Good Evening

    Your question: Studies relating benzo(a)pyrene levels and type 2 diabetes









  • Beatrice Muraguri added an answer:
    What are some of the major domestic ethical issues that have arisen in the recent Ebola epidemic?

    Lots has been written about quarantine and closing borders domestically (US) but not much else.

    Beatrice Muraguri

    Scientists tell us that EVD can still be in the semen for 90 days.We have heard of stories where male survivors forcefully sleep with their wives which is against the advice they receive during discharge.The wives ends up being infected and die another ethical issue 

  • Muhammad Belal Hossain added an answer:
    Is MERS CoV transmitted by the one humped camel (camelus dromedaries)?
    Muhammad Belal Hossain

    Yes, it is evident in some research conducted in middle eastern countries like UAE, KSA etc. Sero-positivity showed the exposure of MERS-CoV in their lifetime.

  • Peizhong Peter Wang added an answer:
    Is it possible to test for significance between medians of two groups?
    To perform a test of significance between means of two groups is well known. But if I use the medians is it possible to test for significance between medians of two groups?
    Peizhong Peter Wang

    This was I did in one of my papers (PMID 12677268):  Can J Gastroenterol. 2003 Mar;17(3):183-6.

    "The 95% CI for means were calculated using the conventional normal distribution method. Because there is no available statistical formula to directly calculate the 95% CI for medians, a bootstrap approach was employed (7,8). This technique involved dividing the total participants into subgroups (replicates), from which a random sample is taken with replacement and a new median was calculated each time. After a large number of such experiments, the lower and upper 95% CI were determined from the values at 2.5% and 97.5% percentiles. All the calculations were performed using SAS 8.0 (SAS, USA)" 

  • Jerry Wesch added an answer:
    Does the MACS cohort data include any information about the health status or mortality of primary partners?

    I have read through the forms and documentation for the Multicenter AIDS Cohort Study several times, and I am not seeing any health data about life partners having been captured. Regarding "blood relatives," there is some. I would assume that this is a result of "no promo homo."

    This hasn't been a bad dream, has it?

    Jerry Wesch

    I spent about 10 years with the MACS study, roughly 1988-98. The MACS started in 1983, I think.  You need to ask John Phair, MD (PI from Northwestern Medical School) or David Ostrow, MD about the full data set. Both are on RG. (I believe David was the author of the original proposal for a multi-center study of the unknown disease killing gay men in the early 1980's.)

    As far as I know, "no promo homo" had no part in the study although there were controversial aspects. The Chicago cohort study site was in "Boys Town" on the north side of Chicago, in Howard Brown Health Center, a community-based LGBT health care center. HBHC had identified some of the index cases of AIDS in Chicago. Most of the cohort management team were from the community. I do not remember if we collected specific SO data although there were many long-term couples in the cohort and we knew who they were. It certainly seems like a good idea in retrospect. The original plan was directed at infectious disease / epidemiology targets, including identification of the disease agent(s), transmission vectors, sexual behavior & virology and only later added psycho-social variables like depression. Eventually MACS developed into a longitudinal study of HIV / AIDS course and treatment.

    It is not a bad dream. Hindsight offers some lessons.

  • Ann Meadow added an answer:
    What variables inside a database represent a patient's socioeconomic status in administrative claims database research?

    When we want to define the socioeconomic state of an enrollee, what variables (items or data) should we look at and collect?

    Ann Meadow

    Measures are poor, and I tend to agree with Frost.  May try address linked to small-area income/poverty rate data (see Hall above); health insurance status/type of health insurance, depending on the circumstances.

  • Sharon Lawn added an answer:
    What is the best measure to rate the core factors influencing the management burden issues that patients with long term conditions are reporting?

    Patients are reporting issues such as poor access to care, availability of socio-economic resources and time; knowledge; and emotional and physical energy. (Bee et al. 2014)

    The work patients must do to care for their health; problem-focused strategies and tools to facilitate the work of self-care; and factors that exacerbate the burden felt (Eton et al 2014)

    Capacity, responsibility, and motivation: a critical qualitative evaluation of patient and practitioner views about barriers to self-management in people with multimorbidity. BMC Health Services Research (Impact Factor: 1.77). 11/2014; 14::536. DOI: 10.1186/s12913-014-0536-y

    Building a measurement framework of burden of treatment in complex patients with chronic conditions: a qualitative study. Patient Related Outcome Measures 2012:3 39–49 http://dx.doi.org/10.2147/PROM.S34681

    Sharon Lawn

    Have you considered the first tool within the Flinders Program - Chronic Condition Care Planning? You'll find details about it at:  http://www.flinders.edu.au/medicine/sites/fhbhru/self-management.cfm

    It's called the 'Partners in Health Scale' and it's a 12 item measure that the person self-rates re their knowledge, relationship with health professionals, access, monitoring and responding, physical, social and emotional impacts, lifestyle, etc. The tool has been validated and used in many research trials and in practice as either a standalone to measure change over time, determine client groupings, determine for services which clients would benefit from care planning, etc.

    It has been adapted into other languages and used in the US, NZ, Australia, Hong Kong and some other countries.

  • Saleh Ameer added an answer:
    Why two groups with same median shows significant difference when using Wilcoxon signed rank test or Mann-Whitney u test?
    Whether the non parametric tests are designed properly?
    Saleh Ameer

    Sorry I only just saw the date of the q.

    A bit late I guess :)

  • Olubusayo Akinola added an answer:
    Can perception of role be independent of exhibited attitude?

    In a sample of healthcare workers, it was deduced that exhibited attitude towards performing a role differs from their perception towards taking up that particular role in a hospital establishment.

    Although this sample exhibited a negative attitude, they had positive perception of their role. It seems to me however, that perception and attitude should go hand in hand, and this sample defies my thinking. Any help?

    Olubusayo Akinola

    Thanks for your prompt response to my question. The two independent variables for the study in question is perception and attitude. Measured with two different validated instruments, one specifically designed to access attitude and the other measures perception. The responses to the questions are Likert scaled. 

  • Manpreet Khurmi added an answer:
    Disease causing Suicidal deaths ?
    Dear Researcher,
    I am very eager to know the answer for this research question.
    What are the disease that can lead to increase the suicidal intend of the patient. Because, I had seen a good number of cases of the patients of HIV/AIDS patients commiting suicide due to lack of hope on the life expectecation, social discrimination, compramised life and Family isolations. But as the same, there may be many disease that which can turns the patient mind into suicidal corner.
    Please share the answer for my question. I would be very happy if anyone interested to share some of the articles and data of the same mentioned above.
    Manpreet Khurmi

    Dear Akshaya, 

    Broadly speaking, Suicides are seen in pts with Chronic depression, Patients on Terminal illnesses etc. However, one needs to differentiate between attempted suicide and a successful suicide as attempt to suicide could be related to heat of the moment e.g. a students who learns he has failed in an exam. Do see these articles that may answer your query: 

    1. Leading causes of death in US: http://www.cdc.gov/nchs/data/nvsr/nvsr61/nvsr61_04.pdf (Suicide is at 10th)

    2. Vulnerability to suicide: http://www.nhs.uk/Conditions/Suicide/Pages/Causes.aspx

    3. Low serotonin levels and suicide: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3819157/


    As a research topic, one should differentiate between Trigger due to Physiological/ Stress (in absence of any pathological condition) reasons and Suicide related to Background of any pathological condition (mental, chronic illness, neoplasia etc). As a secondly aim, mode of execution of suicide may also be studied.  

    Hope this helps!


  • Manpreet Khurmi added an answer:
    Is it necessary to make the medical records data electronic in hospitals in developing countries? What are the benefits?
    In Nepal, most of the hospital's records are disposed of after 5 years, so data is also disposed of. Is it correct to do this? Should it be made electronic? Should Bio-statisticians play a role?
    Manpreet Khurmi

    Hi Brijesh,

    It is important to make Hospital Data electronic. Just sharing some random thoughts:

    1. Epidemiological Information: Who knows which part of the world has the highest burden of the disease? Incidences like Minamata disease just point out to this epidemiological correlate.

    2. In countries where large number of clinical trials are on-going, such information is highly valuable to identify patients who need newer drugs and can benefit from newer treatment regimens. 

    3. Patients who are allergic to a particular drug (or inborn errors of metabolism) could easily be maintained in such clinical histories e.g. sulphonamides.

    4. Such information can help Government to develop Targeted Behaviour Change Communication strategies to change unwanted behaviours.

    5. Can help health financing that is set aside required budget to address health needs of the population e.g. Incidence of Cleft lip/ palate as part of National programme of the country e.g. Rashtriya Bal Swasthya Karyakram.  

    6. Obstetric History: Impact on next pregnancy

    7. Vaccination history: I need not emphasize more 

    Do Note: Patient history is confidential. In no case this should be made public and should be free form data theft.



  • Lateef Mtima added an answer:
    What types of intellectual creations can be the subject matter of IP?

    The history of the human race is a history of the application of imagination, or innovation and creativity, to an existing base of knowledge in order to solve problems or express thoughts. From early writing in Mesopotamia, the Chinese abacus, the Syrian astrolabe, the ancient observatories of India, the Gutenberg printing press, the internal combustion engine, penicillin, plant medicines and cures in Southern Africa, the transistor, semiconductor nanotechnology, recombinant DNA drugs, and countless other discoveries and innovations, it has been the imagination of the world's creators that has enabled humanity to advance to today's levels of technological progress. I am interested in determining what type of intellectual creations can be the subject matter of IP?

    Lateef Mtima

    To provide a non-political answer to the question, today most nations recognize IP protection for utilitarian innovation (machines, drugs, some times methods of doing business) under patent and/or trade secret regimes; for original creative expression (books, art, music) under copyright regimes; restricting commercial exploitation of an individual's name, likeness, or persona under publicity rights (not as widely recognized as other forms of IP); and for distinctive source indicators of products or services under trademark regimes. Those are the major categories of innovative or creative output typically recognized as IP; the key is fitting the out put into one of these regimes AND satisfying the regime's particular prerequisites to protection (for example, in the US, fixation in a tangible medium such as on paper or film is a prerequisite to copyright protection, which is not the case for some other copyright regimes).

  • Olubusayo Akinola added an answer:
    Can I compare the results of a PCA from a study with mine using the same questionnaire?

    I would like to know if its possible to compare the factor loadings obtained from a particular survey with mine using the same questionnaire. This is to enable me to establish the variables capable of explaining the observed variance in my study and to confirm if there are differences in the item loadings.  

    Olubusayo Akinola

    Thank you Dr Filipe for being so explicit, I found the links very useful and I feel more confident to continue with my analysis. I also appreciate Prof David, it's a privilege that you look through my questions. Thank you. 

  • Paresh Chandra Ghosh added an answer:
    Has anyone examined the effect of breast size on the biomechanics of lifting in industry or health care?

    Seems like women with larger breasts would have to carry objects further from the body, with effects on lifting efficacy.  But I can't find anything about this.

    Paresh Chandra Ghosh

    Yes I do agree with myor her view is considerate.let us leave together some disadvantage of this nature man can help women so peaceful co existence is best. Beside pursue some research to really understand it is problem or not. pcg Chennai

  • Sandro Rolesu added an answer:
    How does one link altitude to a dataset containing latitude and longitude?

    I would like to analyse my data by altitude, however I do not have this information in my dataset. Latitude and longitude are recorded. Is there a look-up table which would allow me to link this to altitude?

    Edited for clarification: I am using Health Survey data. I would like to examine various participant characteristics by altitude. I have the latitude and longitude for addresses of all the respondents in my survey data. I do not have any data on altitude. Does a dataset exist that is open-access, that I could download and use to link altitude to my existing data?

    Sandro Rolesu

    You can download altimetry 30x30 meters (ASTER GDEM data) based on satellite observation, at the link: http://www.jspacesystems.or.jp/ersdac/GDEM/E/4.html 

  • Ali Abdil Razzaq Muhammed Noori Aldallal added an answer:
    Where we can get a current epidemiological status of obesity and insulin resistance?
    Is there any specific site for current epidemiological status?
  • Gonzalo Marchant Gonzalez added an answer:
    Do you know what the recommendation is for physical activity and sedentary behavior to health?
    We know that there are many determinants and barriers to physical activity. Among them are the extrinsic factors such as environmental, socioeconomics, and sociopolitical as intrinsic motivation, self-perception, self-efficacy and level of knowledge.
    My questions are: Are people becoming inactive due to lack of knowledge of practical recommendations for physical activity, as well as the volume and intensity to achieve health benefits? Would an intervention program based on the recommendations of health would increase levels of physical activity?
    Gonzalo Marchant Gonzalez

    Hello Philippe, 

    To answer to your questions. I can suggest to you 2 articles that could be very useful:

    - Are people becoming inactive due to lack of knowledge of practical recommendations for physical activity, as well as the volume and intensity to achieve health benefits?

    1. The main point is that people become inactive because the environment reduce the places and stimulus to be active (e.g. escalators, elevators, cars and sedentary work time). People recognize Physical inactivity as health-harming and yet continue to engage in. There is no lack of knowledge of recommendations, its a lack of control over behavior, awareness and consciousness, that means Habit and automatic processes that guide the human behavior. Read the first attached article about "Changing human behaviors".

    - Would an intervention program based on the recommendations of health would increase levels of physical activity?

    2. The most part of interventions aimed at changing behaviors have largely encouraged people to reflect on their behaviors (intentions, decisions,motivations or the social cognitive theories like “Theory of Planned Behavior”). Meanwhile, these approaches are often ineffectual, which is in keeping with the observation that much human behavior is automatic, cued by environmental stimuli, resulting in actions that are largely unaccompanied by conscious reflection.

    The automatic aspect of human behavior: lack of intentionality, low degree of control over the behavior, lack of awareness and efficiency (Bargh, 1994), it is crucial for the understanding of the habit and his role in the regular and long-term adoption of health-related behaviours (Lally, Chipperfield & Wardle, 2008). 

    If we consider these features of human behavior, i am afraid to say that an intervention program based on the recommendations of health would not increase the levels of physical activity. In fact, you must pay attention to the measure to asses physical activity levels. Read the second attached article about "Habits".

    I hope that my answer could be useful for you. 

    Best wishes, 


    + 1 more attachment

  • M. Ricky Ramadhian added an answer:
    Can we use mean+/-standard error instead of mean+/-standard deviation when data is non-parametric?
    I measured cytokines through ELISA in humans, but my values were very skewed since I got huge standard deviation which was nearly 2 fold larger than my mean value.
    Shall I use mean+/-standard error instead of mean+/-standard deviation when data is non-parametric?
    M. Ricky Ramadhian

    how about this data if we have data like this?

  • Greger Lindberg added an answer:
    What impact will labeling obesity as a disease have on primary prevention of childhood obesity?
    The American Medical Association has now joined other organizations in deeming obesity a disease (not just a condition or syndrome). There is hand-wringing about proliferation of pharmaceuticals, surgery, and other medical treatments. What about prevention, and specifically, primary prevention for children? Is there applicable evidence for other diseases to inform us of what to expect for prevention and public health efforts around childhood obesity?
    Greger Lindberg

    Weight essentially reflects energy intake minus energy expenditure. I think it is wrong to focus on energy intake. We should direct our attention to energy expenditure. A sedentary lifestyle in itself is a strong risk factor for disease and also for obesity. Concentrating on energy intake is rather useless if we do nothing to increase energy expenditure. The latter is probably also much easier to change whereas changing energy intake has at best a short-term but marginal effect on weight.

  • Masimalai Palaniyandi added an answer:
    What is the forward elimination method, SPSS- forward selection or backward elimination?

    Data was analysed by SPSS software and the authors mentioned that in the multivariate logistic regression analysis they used forward elimination method

    Masimalai Palaniyandi

    Dear friend Yan Chen,

    The both backward and frontward selection or removal methods are used to find the influence of potential confounders (independent variables) and statistical significance on the dependant variables. it is built in or with in Linear Multivariate regression model to see the stepwise regression analysis to see the influence of single variable and multiple variables and also compound variables or factors.


  • Javad Amani added an answer:
    How we can find the Cut off score of the Scale tool?
    Suppose I have a Questionnaire for a Stress assessment that contains 30 questions, each question has 5 answers (0- no stress, 1-mild stress, 2- moderate , 3-High stress, 4- Severe stress). The Total score of the 30 question varies from 0 - 120.

    How we can categories the Total score (the range of total score is 0-120) into mild , moderate and severe? Which cut off s should l take for mild, moderate and severe?
    Javad Amani

    for likert scale 1 to 2.33 (low), 2.34 to 3.67 (moderate), 3.67 to 5 (high). to do this you should change scoring of your scale from 1 to 5 for each item. then compute the mean of your scale (not sum) and use above method to cut off

  • Sultan Salah added an answer:
    What type of statistical analysis should be done in a survey study ?
    In a survey done in a large population like about 5000 subjects, how to analyze the results statistically ?
    Sultan Salah

    Input from the statistician will be of immense help in the conduct of the study and will also help in publication of the study in the reputed journal, nowadays there are various ready made software available in the  market . SPSS is widely used in the statistical analysis and accepted by many reputed journals.

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Identifying patterns of health and disease among populations.

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