Topnotch Medical Board Prep - Preventive Medicine and Public Health - April 2024 PDF

TOPNOTCH MEDICAL BOARD PREP PREVENTIVE MEDICINE AND PUBLIC HEALTH MAIN HANDOUT BY DR. MANN For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/ This handout is only valid for April 2024 PLE batch. This will be rendered obsolete for the next batch sin...

TOPNOTCH MEDICAL BOARD PREP PREVENTIVE MEDICINE AND PUBLIC HEALTH MAIN HANDOUT BY DR. MANN For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/ This handout is only valid for April 2024 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly. BRIDGE KIND OF HOST 1. Definitive Host o a host in which the parasite reaches maturity and, if possible, reproduces sexually 2. Reservoir Host o can harbor a pathogen indefinitely with no ill effects 3. Intermediate Host o host that harbors the parasite only for a short transition period, during which (usually) some developmental stage is completed. 4. Paratenic Host o host is similar to an intermediate host, only that it is not needed for the parasite's development cycle to progress. o Paratenic hosts serve as "dumps" for non-mature stages of a parasite in which they can accumulate in high numbers. 5. Dead-end host or incidental host o is an intermediate host that generally does not allow transmission to the definitive host, thereby preventing the parasite from completing its development. 6. Host of predilection o is the host preferred by a parasite 7. Amplifying host o is a host in which the level of pathogen can become high enough that a vector such as a mosquito that feeds on it will probably become infectious Balikan niyo yung micro niyo! Paulit ulit!... J Dr. Mann • DEFENSE MECHANISM OF THE HOST: • Specific anatomical defenses • Immunity • Resistance • Tolerance • Allergy • State of nutrition III – ENVIRONMENT • Sum total of an organism’s external surrounding conditions and influences that affects the life and development of an organism 3 CATEGORIES OF ENVIRONMENT: PHYSICAL BIOLOGIC SOCIO-ECONOMIC Climate Serve as • Working condition reservoirs • Temperature • Level of industrialization and vectors • Disruption: Disaster/ war • Altitude of disease • Humidity • Availability of medical agents services Geography/ • Period of prosperity and Location depression • Sanitation and Housing SUPPLEMENT Burden of Disease (Philippines, 2022) Top 10 Leading Causes of Morbidity 1. Acute Respiratory Infection 2. Hypertension 3. Animal Bites 4. Acute Lower Tract Respiratory Infection 5. Urinary Tract Infection 6. Skin Disease 7. Influenza-like Illness 8. TB All Forms 9. Acute Watery Diarrhea 10. Acute Febrile Illness • EPIDEMIC – an increase, often sudden, in the number of cases of a disease above what is normally expected in that population in that area. (There MUST be an increase from the baseline!) • OUTBREAK – same definition of epidemic, but is often used for a more limited geographic area • PANDEMIC – refers to an epidemic that has spread over several countries or continents, usually affecting a large number of people (worldwide epidemic) • SPORADIC – refers to a disease that occurs infrequently and irregularly MATCHING TYPE 1. 22 Cases of legionellosis occurred A. Sporadic Disease within 3 weeks among residents of B. Endemic Disease a particular neighborhood (usually C. Hyperendemic 0 or 1 per yr) Disease 2. Average annual incidence was D. Pandemic Disease 364 cases of pulmonary E. Epidemic Disease tuberculosis per 100,000 population in one area, compared with national average of 134 cases per 100,000 3. Over 20M people worldwide died from influenza in 1918-1919 4. Single case of histoplasmosis was diagnosed in a community 5. About 60 cases of gonorrhea are usually reported in this region per week, slightly less than the national average. Principles of Epidemiology in Public Health Practice Third Edition Answers: ECDAB ESSENTIAL INGREDIENTS OF AN EPIDEMIC • A recent increase in dosage or change in virulence of the pathogenic agent • the recent introduction of the pathogen into a setting where it has not been before • an enhanced method of transmission so that more susceptible are exposed • some change in the susceptibility of the host response to the pathogenic agent • cultural or behavioral factors that increase host exposure or involve introduction through new portals of entry GENERATION TIME • The period between the receipt of infection by the host and the maximal communicability of that host. • Roughly equivalent to the incubation period, the interval between the receipt of infection and the onset of illness. • Can be used to measure the rate of an epidemic o When one person transmits an infection to another, then the time that elapses between onset of symptoms in the primary case and onset of symptoms of the secondary case Source: May 2022 FHSIS Preliminary Data, DOH Based on the above data from PSA and DOH the top causes of mortality in the country consists of non-communicable diseases, which can be a result of unhealthy behaviors, modifiable risk factors, and the sociopolitical conditions affecting the communities. Meanwhile, the top leading causes of morbidity are generally communicable diseases influenced heavily by the environmental conditions such as unsafe drinking water, poor sanitation and hygiene and indoor and outdoor air pollution. Dr. Tan EPIDEMIC DISEASE OCCURRENCE DEFINITION OF TERMS • ABSENCE OF DISEASE – no cases on record; disease absent from the beginning or it has been eradicated • ENDEMIC – habitual presence of a disease within a given geographic area, also refers to the usual occurrence of a given disease within such an area • HYPERENDEMIC – refers to persistent, high levels of disease occurrence © Topnotch Medical Board Prep EPIDEMIC CURVES • shows the frequency of new cases over time based on the date of onset of disease • The shape of the curve in relation to the incubation period for a particular disease can give clues about the source TOPNOTCH MEDICAL BOARD PREP PREVENTIVE MEDICINE AND PUBLIC HEALTH MAIN HANDOUT BY DR. MANN For inquiries visit www.topnotchboardprep.com.ph or email us at [email protected] This handout is only valid for the April 2024 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly. Page 6 of 77 TOPNOTCH MEDICAL BOARD PREP PREVENTIVE MEDICINE AND PUBLIC HEALTH MAIN HANDOUT BY DR. MANN For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/ This handout is only valid for April 2024 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly. TYPES OF EPIDEMIC PATTERNS • Epidemics can be classified according to their manner of spread through a population: o Common-source § Point § Continuous o Propagated o Mixed o Other PROPAGATED OUTBREAK • results from transmission from one person to another • usually have a series of successively larger peaks, which are one incubation period apart • The successive waves tend to involve more and more people, until the pool of susceptible people is exhausted or control measures are implemented COMMON SOURCE OUTBREAK • one in which a group of persons are all exposed to an infectious agent or a toxin from the same source. POINT-SOURCE OUTBREAK • Type of common-source outbreak – If the group is exposed over a relatively brief period so that everyone who becomes ill does so within one incubation period • Exposure of susceptible population at the same time (1 incubation period) to common source of pathogen. • Exposure is brief (single exposure). • Epidemic curve rises & fall rapidly usually skewed to the right o typically have a steep upslope and a more gradual downslope • Single, brief exposure that did not persist over time • All cases have single incubation period • No person to person spread • E.g. contaminated food or an infected food handler The epidemic curve shown above is from an outbreak of measles that began with a single index case who infected a number of other individuals. (The incubation period for measles averages 10 days with a range of 7-18 days.) One or more of the people infected in the initial wave infected a group of people who become the second wave of infection. So here transmission is person-to-person, rather than from a common source Dr. Mann • MIXED EPIDEMICS • Involve both single common exposure to an infectious agent and secondary propagative spread to other individuals, usually by person to person transmission The figure above is an example of epidemic curve -number of cases during an epidemic were plotted over time. The epi-curve above is an example of epidemic of hepatitis A among patrons of a restaurant who ate green onions, each had a point source of exposure. Dr. Mann • For example, a common-source epidemic of shigellosis occurred among a group of 3,000 women attending a national music festival (Figure 1.24). Many developed symptoms after returning home. Over the next few weeks, several state health departments detected subsequent generations of Shigella cases propagated by person-to-person transmission from festival attendees. • CONTINUOUS COMMON-SOURCE OUTBREAK HERD IMMUNITY IN THE CONTEXT OF COMMUNICABLE DISEASES • Herd immunity o Herd immunity is a term used to describe a situation where enough of a community is immune to an infectious process to prevent person-to-person spread SUPPLEMENT: • may also rise to a peak and then fall, but the cases do not all occur within the span of a single incubation period. This implies that there is an ongoing source of contamination The epidemic curve above is from the cholera outbreak in the Broad Street area of London in 1854 that was investigated by Dr. John Snow. Cholera has an incubation period of 1-3 days, and even though residents began to flee when the outbreak erupted, you can see that this outbreak lasted for more than a single incubation period. This suggests an ongoing source of infection, in this case, the Broad Street pump • Dr. Mann Dr. Mann Black circles show individuals infected by a contagious disease, white circles are individuals who are not affected, and the grey circle represents the one person who was immune. The arrows show the direction of transmission. In A, all individuals were susceptible, and all were affected. In B, only one individual was immune, yet four were protected, even though three of them were susceptible • TOPNOTCH MEDICAL BOARD PREP PREVENTIVE MEDICINE AND PUBLIC HEALTH MAIN HANDOUT BY DR. MANN For inquiries visit www.topnotchboardprep.com.ph or email us at [email protected] This handout is only valid for the April 2024 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly. Dr. Mann Page 7 of 77 TOPNOTCH MEDICAL BOARD PREP PREVENTIVE MEDICINE AND PUBLIC HEALTH MAIN HANDOUT BY DR. MANN For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/ This handout is only valid for April 2024 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly. EXPLORING OCCURRENCE OF DISEASE • When a disease appears to have occurred at more than an endemic level, and we wish to investigate its occurrence, we ask: o Who was attacked by the disease? (Person) o When did the disease occur? (Time) o Where did the cases arise? (Person) WHO • The characteristics of the human host are clearly related to disease risk. Factors such as sex, age, and race have a major effect PERSON • Age: diseases with different age patterns o Magnitude decreasing with age: disease confers long lasting immunity o Magnitude increasing with age: degenerative diseases o Magnitude high at both extremes of age: reflects low resistance of the young and old o Great exposure during the middle age • Sex: sex differential because of sexual constitution/make up o Greater exposure of males, greater health consciousness of females: early consultation, diagnosis and treatment, more cases recorded • Civil risk factors: o Married at higher risk for cervical CA o Greater family support among the married • Socio-economic status o TB and H. Pylori (low socio-economic status) o Gout –“Disease of kings”, tennis elbow( high socio-economic status) • Ethnic and racial groups – Differences in racial, ethnic, or other group variables may reflect differences in susceptibility or exposure, or differences in other factors that influence the risk of disease • State of Nutrition o Malnourished at higher risk for opportunistic infections o Obese at higher risk for CVS diseases WHEN • Certain diseases occur with a certain periodicity TIME (TEMPORAL VARIATION) Secular Long term fluctuation of disease occurrence (Long)Trend over many decades Increase in # of cases more or less regularly Cyclic Intrinsic every around 5 years due to accumulation of Variation susceptible through births; exhibited by diseases that confer long lasting immunity Fluctuation of disease occurrence during a Seasonal year reflecting climactic changes (Dengue, Variation leptospirosis, influenza) WHERE • Disease is not randomly distributed in time or place PLACE International Related to geographic variation as well as Variation race, ethnicity and culture Results from differences in socio economic National development as well as cultural and Variation geographic differences Related to environmental and access to health differences (Sex linked dystonia Local Variation parkinsonism (XDP), Malaria, Schistosomiasis) CRITERIA FOR INITIATING AN INVESTIGATION • If the disease is a priority • When the disease exceeds the usual expected frequency • Cases are due to common sources • When the disease seems to be more severe • When a disease has not previously occurred for a long time in a place a. Time course by frequency polygon or histogram b. Place: geographical extent of problem c. Person: Population at risk 6. Develop hypothesis 7. Evaluate hypothesis – uses cohort &case-control studies 8. Execute additional studies and refine hypothesis 9. Implement control, and prevention measures (Sanitation, Prophylaxis, Diagnosis and treatment, and Vector Control) 10. Communicate findings 11. Follow up recommendations https://www.cdc.gov/csels/dsepd/ss1978/lesson6/section2.html SUPPLEMENT: ATTACK RATE An attack rate is defined as: !"#$%& () *%+ ,-.%. () - /0.%-.% !"#$%& () 1%&.(* %23(.%/ 0* - 3-&40,"5-& ("4$&%-6 x 100 In this equation, 100 is used as the constant multiplier so the rate can be expressed as a percentage. Dr. Mann • A person who acquires the disease from that exposure (e.g., from a contaminated food) is called a primary case • A person who acquires the disease from exposure to a primary case is called a secondary case. • The secondary attack rate – defined as the attack rate in susceptible people who have been exposed to a primary case SUPPLEMENT: ICEBERG PHENOMENON • The visible part of the iceberg denotes the clinically apparent cases of disease in the community. • The part of the iceberg below the water level denoted the latent, subclinical, undiagnosed and carrier states in the community, which forms the major part. Iceberg Phenomenon, as Illustrated by a Diphtheria Epidemic in Alabama. • Alabama. In epidemics, the number of people with severe forms of the disease (part of iceberg above water as shown here by 2 patients who died and 12 patients with symptoms of clinical illness) may be much smaller than the number of people with mild or asymptomatic clinical disease (part of iceberg below water as shown by the 32 “invisible” cases that would have remained invisible without extensive epidemiologic surveillance). Elmore, Joann G.. Jekel's Epidemiology, Biostatistics and Preventive Medicine EPIDEMIOLOGIC STUDIES DESCRIPTIVE EPIDEMIOLOGY ANALYTICAL EPIDEMIOLOGY INTERVENTION OR EXPERIMENTAL EVALUATION EPIDEMIOLOGY Concerned with disease distribution and frequency Analyze the causes or determinants of disease by testing hypothesis Clinical and community trials about effectiveness of new methods for controlling diseases Measure of the effectiveness of different health services and programs STEPS IN OUTBREAK INVESTIGATION 1. Field work 2. Establish existence of an outbreak 3. Verify diagnosis- uses frequency distributions 4. Define and identify cases 5. Perform descriptive epidemiology; characterize: TOPNOTCH MEDICAL BOARD PREP PREVENTIVE MEDICINE AND PUBLIC HEALTH MAIN HANDOUT BY DR. MANN For inquiries visit www.topnotchboardprep.com.ph or email us at [email protected] This handout is only valid for the April 2024 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly. Page 8 of 77 TOPNOTCH MEDICAL BOARD PREP PREVENTIVE MEDICINE AND PUBLIC HEALTH MAIN HANDOUT BY DR. MANN For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/ This handout is only valid for April 2024 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly. TYPES OF EPIDEMIOLOGIC STUDIES DESCRIPTIVE STUDIES ANALYTICAL STUDIES • Describes the distribution • Concerned with of cases by the variables of determining causes of person, time and place in disease occurrence, order to: specifically whether a o Study and explain acute suspected factor is causally outbreaks of disease associated with disease o Follow secular trends of using observational disease occurrence over method of testing time hypothesis or cause o Develop hypothesis of • goes further by analyzing disease transmission relationships between • limited to a description of health status and other the occurrence of a disease variables in a population and is often the first step in an epidemiological investigation • Used if little is known • Purpose is to test the about event or hypothesis because you phenomenon. The purpose already know the is to generate hypothesis relationship of events. TIP: One way of knowing if the question warrants for a descriptive study or analytical study is looking at the construction of the case. If it uses “MAYBE associated” then the use of descriptive study is logical. While if the case presents with words like… “With Significant Relationship or Is related with”. Then, an analytic design is appropriate. Dr. Mann TYPES OF EPIDEMIOLOGIC STUDIES ALTERNATIVE NAME TYPE 1. OBSERVATIONAL DESCRIPTIVE Case Report Case Series Ecological Study Cross-sectional ANALYTICAL Cross-section Case-Control Cohort 2. EXPERIMENTAL Randomized Controlled Trials Field Trials Community Trials UNIT OF OBSERVATION Single patient Group of patients Correlational Prevalence Survey Prevalence Study Case Reference Follow-up Individuals Individuals Individuals Clinical Trials Therapeutic Trials Prophylactic Trial Community Intervention Study Patients Healthy people Communities Modified from Basic epidemiology 2nd edition (WHO) OBSERVATIONAL DESCRIPTIVE EPIDEMIOLOGY DESCRIPTIVE STUDY DESIGNS CASE REPORT “INTERESTING CASE” • Most basic; brief objective report of a clinical characteristic or outcome from a single clinical subject or event. • Highlights the UNAWARENESS of case (ex: adverse drug effect; advanced proliferative diabetic retinopathy) • Methodology: o Identify single noteworthy case o Retrospective data collection o No statistical analysis • Advantages: o Address almost all clinical question or issue; commonly used to report unusual or unexpected events • Disadvantages: o Only few conclusions can be drawn based on evidence o Results are rarely generalizable o Susceptible to bias CASE SERIES • Objective report of a clinical characteristic or outcome from a group of clinical subjects with similar diagnosis, collection of individual case reports which may occur within fairly short period of time • Highlights the SIMILARITIES of case • Methodology: o Identify subjects with regard to clinical events in question o Retrospective or prospective data collection BUT a control group is usually not included o Descriptive statistics are calculated o Results are strengthened when consecutive series of subjects are included over a period of time • Advantage: Easy to conduct and less time and financial use • Disadvantages: o Limited generalizability because of bias, lack of control group o Absence of comparison, not conclusive ECOLOGIC STUDIES (CORRELATIONAL) • The unit of analysis is a group most often defined geographically (urban vs. rural; mountainous region, area with wells as major water source) • Measures that represent characteristics of entire population, used to describe disease in relation to some factors of interest. • Seeks to determine the extent to which two characteristics are related. • Aggregate risk factors CROSS-SECTIONAL SURVEYS (PREVALENCE SURVEYS) • A simple descriptive account of interesting characteristics observed in a group of patients. • Case finding, special surveys to establish incidence or prevalence • Also called prevalence surveys because they focus on a point in time • Exposure and effect at the same time o On a topic or variables of interest which may include the frequency of disease or health disorder, factors associated with health and disease, attributes of positive health. • Advantages: o Relatively simple and rapid; o Can be extended to a case control or cohort study; o Allows the study of the association of a disease with a wide range of factors simultaneously; o Feasible as long as prevalence of condition is high o Convenient for sudden outbreaks • Disadvantages: o Not suitable for rare or acute disease o Factors which may prolong or shorten the duration of the condition may not be seen o Difficult in interpreting temporal sequence of cause and effect o Provides only a snap shot in time. o Selection bias OBSERVATIONAL ANALYTICAL EPIDEMIOLOGY • Common Applications: o Community diagnosis o Investigation of epidemic o Determination of diseases etiology o Evaluations of community interventions and programs • May be observational or experimental: Observational Experimental • Cross-Sectional • Field/Community Trials • Case-Control • Clinical Trials • Cohort ANALYTIC STUDY DESIGNS Ngayon ka pa ba susuko? DOC!!!!! Please basahin mo ito, kapag may tiyaga may linaga! Patience is a virtue, read the whole text please… J) Dr. Mann CROSS-SECTIONAL ANALYTIC (PREVALENCE STUDY) • Examines the relationship between diseases and other variable of interest as they exist in defined population at one particular point in time. • Subject selection at random. • Employs inferential statistics (p value) to determine association or relationship using chi square test. • Uses: o Determine the magnitude of a disease o Hypothesis generation o Evaluation of medical care and health service delivery o Establish baseline data o Studying conditions that are quantitatively measured and that vary over time or relatively frequent diseases that have long duration TOPNOTCH MEDICAL BOARD PREP PREVENTIVE MEDICINE AND PUBLIC HEALTH MAIN HANDOUT BY DR. MANN For inquiries visit www.topnotchboardprep.com.ph or email us at [email protected] This handout is only valid for the April 2024 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly. Page 9 of 77 TOPNOTCH MEDICAL BOARD PREP PREVENTIVE MEDICINE AND PUBLIC HEALTH MAIN HANDOUT BY DR. MANN For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/ This handout is only valid for April 2024 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly. • Advantages: o Conducted quickly o Provides data on a disease rate in a population and descriptive information on other characteristics of the population o Can identify easily stage of disease before it becomes apparent clinically o Less costly than cohort • Disadvantages: o Measures the effect of both incidence and duration; o Cannot identify direction of etiologic association (temporal sequence) o Sensitive to response bias o Observation bias can easily occur since both are measured simultaneously CASE-CONTROL • Persons with a given disease (cases) and persons without the disease (controls) are selected. The proportion of cases and controls of being exposed to a probable risk factor are determined and compared for presence of association. • Starts with the outcome then researcher will be looking for any exposure or factors. OUTCOME → EXPOSURE • Issues: o Selection bias o Observation bias – can be avoided by making the procedures to obtain information as similar as possible or by blinding the investigator o Recall bias o Misclassification – errors in categorization of either exposure or disease status • Example: Comparison of prior estrogen use, in uterine CA patients to that in age-matched controls without CA to assess possible risk of uterine CA SUPPLEMENT THALIDOMIDE A classic example of a case-control study was the discovery of the relationship between thalidomide and limb defects in babies born in the Federal Republic of Germany in 1959 and 1960. The study, done in 1961, compared affected children with normal children. Of 46 mothers whose babies had malformations, 41 had been given thalidomide between the fourth and ninth weeks of pregnancy, whereas none of the 300 control mothers, whose children were normal, had taken the drug during pregnancy. Accurate timing of the drug intake was crucial for determining relevant exposure. What do you call that condition that involves malformations of the arms and legs that is usually associated with thalidomide? Mga besh SAGOT?............. Phocomelia Dr. Mann DESIGN OF A CASE-CONTROL STUDY Basic epidemiology 2nd edition (WHO) COHORT • Exposed and non-exposed populations are identified and followed prospectively over time to determine the rate of a specific clinical disease or event. • Also used in clinical decision analysis to address the predictive value of test positivity or negativity. • Starts with the factors/ exposure then researcher will be looking for outcome • At the time exposure status is defined, all potential subjects must be free from the disease under investigation • Best information about disease causation EXPOSURE → OUTCOME • Done only if there is significant association. • Uses: o Address issues relating to risk factors o Used in clinical decision analysis to assess the differences in test positivity between diseased and non-diseased population • Advantages: o Provide the opportunity to investigate rare diseases as well as those with long period of latency o Less time consuming and less expensive to carry out o Require smaller sample size o Allow for the evaluation of a wide range of potential etiologic exposure o For diseases with long lag • Disadvantages: DESIGN OF A COHORT STUDY o Disease status is measured as a dichotomous categorical variable; Basic epidemiology 2nd edition (WHO o Disease status of the subject is likely to influence ascertainment of exposure factor; o Temporal relationship between exposure and disease may be difficult to establish in some situation; o Has to deal with the problem of selective survival, differential reporting of exposure information between study groups • Types: based on their disease status and differential selection of o Retrospective: all relevant events (both exposure and either the cases or controls on the basis of their exposure outcome of interest) have already occurred when the study is status; initiated. o Information on the potential risk factor and confounders may o Prospective: relevant exposure may or may not have occurred not be available either from records or the subject’s memories at the time the study is begun but the outcome has not yet o Inferential statistics: ODDS RATIO (OR)!!!! occurred • Selection of cases Hospital- based Population-based • Convenient • Avoids bias • Less expensive • More expensive • Prone to selection bias o Incident cases preferable to prevalent o Prevalent cases reflect not only determinants of disease but those of duration as well. • Selection of controls • Uses: o Depends on the characteristics and source of the cases, o Describe the natural history of disease practical and economic considerations o Identify the number of new cases for planning health care o Disadvantages using controls from the general population: services & determine effectiveness of preventive measures o More costly and time consuming o Determine the etiologic factors associated with the onset of disease o Difficulty in contacting healthy people o Example: The association between low birth weight and maternal o Availability of population smoking during pregnancy can be studied by obtaining smoking o Quality of information may not be the same – general histories from women at the time of prenatal visit and then population may not recall exposures with the same level of subsequently correlating birth weight with smoking histories accuracy as that of cases TOPNOTCH MEDICAL BOARD PREP PREVENTIVE MEDICINE AND PUBLIC HEALTH MAIN HANDOUT BY DR. MANN Page 10 of 77 For inquiries visit www.topnotchboardprep.com.ph or email us at [email protected] This handout is only valid for the April 2024 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly.