research assignment

Assignment 2 (Study Designs)

1) In which study design does the researcher assign the exposed/unexposed status?

· Randomized Controlled Trial

· Cohort study

2) In which study design does the researcher assess the exposed/unexposed status?

· Randomized Controlled Trial

· Cohort study

3) Research is never perfect; different errors can occur. For instance, during a randomized controlled trial, a participant aware of his/her exposure status may behave differently due to the belief that their behavior should change in response to a drug. This is known as the placebo effect. Similarly, an observer may only observe the behaviors that confirm his/her hypothesis. Mention and explain a method that may help prevent such biases.

4) Which of the following assesses the effect of an exposure on an outcome under ideal conditions?

· Efficacy

· Effectiveness

5) Which of the following assesses the effect of an exposure on an outcome under real-world conditions?

· Efficacy

· Effectiveness

6) Mention the type of cohort design each of the following pictures presents and briefly explain it.

Picture 1:

a) Cohort study type:

b) Description:

Picture 2:

a) Cohort study type:

b) Description:

For each of the following abstracts, identify the following:

 Population – who is the patient or what problem is being addressed?

 Intervention/exposure – what is the intervention or exposure?

 Comparison group (if available) – what is the comparison group?

 Outcome – what is the outcome or endpoint?

 STUDY DESIGN

ABSTRACT #1

Pediatr Infect Dis J. 2010 May;29(5):397-400.

Lack of association between measles-mumps-rubella vaccination and autism in children: […].

Mrozek-Budzyn D, Kiełtyka A, Majewska R.

Abstract

OBJECTIVE: The first objective of the study was to determine whether there is a relationship between the measles-mumps-rubella (MMR) vaccination and autism in children. The second objective was to examine whether the risk of autism differs between use of MMR and the single measles vaccine.

DESIGN: […]

STUDY POPULATION: The 96 patients […] with childhood or atypical autism, aged 2 to 15, were included into the study group along with […] 192 children individually matched […] by year of birth, sex, and general practitioners.

METHODS: Data on autism diagnosis and vaccination history were from physicians. Data on the other probable autism risk factors were collected from mothers. Logistic conditional regression was used to assess the risk of autism resulting from vaccination. Assessment was made for children vaccinated (1) Before diagnosis of autism, and (2) Before first symptoms of autism onset. Odds ratios were adjusted to mother's age, medication during pregnancy, gestation time, perinatal injury and Apgar score.

RESULTS: For children vaccinated before diagnosis, autism risk was lower in children vaccinated with MMR than in the nonvaccinated (OR: 0.17, 95% CI: 0.06-0.52) as well as to vaccinated with single measles vaccine (OR: 0.44, 95% CI: 0.22-0.91). The risk for vaccinated versus nonvaccinated (independent of vaccine type) was 0.28 (95% CI: 0.10-0.76). The risk connected with being vaccinated before onset of first symptoms was significantly lower only for MMR versus single vaccine (OR: 0.47, 95% CI: 0.22-0.99).

CONCLUSIONS: The study provides evidence against the association of autism with either MMR or a single measles vaccine.

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ABSTRACT #2

Ann Thorac Surg. 2009 Aug;88(2):537-42.

Efficacy of acupuncture in prevention of postoperative nausea in cardiac surgery patients.

Korinenko Y, Vincent A, Cutshall SM, Li Z, Sundt TM 3rd.

Abstract

BACKGROUND: Coronary artery bypass graft and cardiac valve surgeries are frequently performed in medical facilities in the United States, and postoperative nausea (PON) is a prevalent problem in this patient population. The purpose of this study was to evaluate the efficacy of a single preoperative acupuncture treatment in the prevention of PON in patients undergoing coronary artery bypass graft or cardiac valve surgery, or both.

METHODS: Ninety participants presenting for coronary artery bypass graft or cardiac valve surgery, or both, were recruited for this study. Patients were randomly assigned to receive either one preoperative acupuncture and standard postoperative care (acupuncture group) or solely standard postoperative care (control group). Acupuncture was performed 0.5 to 3 hours before surgery. The PON incidence and severity on postoperative day (POD) 2 and POD 3 were measured with validated nausea tools.

RESULTS: The acupuncture group had a significantly lower incidence of nausea compared with the control group (POD 2, odds ratio [OR], 0.38; p = 0.05; and POD 3, OR, 0.26; p = 0.01). The acupuncture group also had a significantly lower score of nausea severity than the control group (POD 2, OR, 0.29; p = 0.01; and POD 3, OR, 0.25; p = 0.01). No adverse effects due to acupuncture treatment were reported. Antiemetics, pain medications, and anesthetics administered intraoperatively did not differ between the two groups and did not influence study results.

CONCLUSIONS: A single preoperative acupuncture treatment decreased incidence and severity of PON in patients undergoing coronary artery bypass graft or cardiac valve surgery, or both, and caused no adverse effects.

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ABSTRACT #3

Am J Obstet Gynecol. 2009 Feb;200(2):151.e1-9; discussion e1-5. Epub 2008 Dec 13.

Inherited thrombophilia and preeclampsia within a multicenter cohort: the Montreal Preeclampsia Study.

Kahn SR, Platt R, McNamara H, Rozen R, Chen MF, Genest J Jr, Goulet L, Lydon J, Seguin L, Dassa C, Masse A, Asselin G, Benjamin A, Miner L, Ghanem A, Kramer MS.

Abstract

OBJECTIVE: We sought to evaluate the association between inherited thrombophilia and preeclampsia.

STUDY DESIGN: From a multicenter cohort of 5337 pregnant women, we prospectively identified 113 women who developed preeclampsia and selected 443 control subjects who did not have preeclampsia or nonproteinuric gestational hypertension. Blood samples were tested for DNA polymorphisms affecting thrombophilia (factor V Leiden mutation, prothrombin G20210A mutation, methylenetetrahydrofolate reductase C677T polymorphism), homocysteine, and folate levels, and placentae underwent pathological evaluation.

RESULTS: Thrombophilia was present in 14% of patients and 21% of control subjects (adjusted logistic regression odds ratio, 0.6; 95% confidence interval, 0.3-1.3). Placental underperfusion was present in 63% of patients vs 46% of control subjects (P < .001) and was more frequent in women with folate levels in the lowest quartile (P = .04), but was not associated with thrombophilia.

CONCLUSION: We did not find evidence to support an association between inherited thrombophilia and increased risk of preeclampsia. Placental underperfusion is associated with preeclampsia, but this does not appear to be consequent to thrombophilia.

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ABSTRACT #4

CMAJ. 2006 Dec 5;175(12):1560-2.

Early to bed and early to rise: does it matter?

Mukamal KJ, Wellenius GA, Mittleman MA.

Abstract

BACKGROUND: Controversy remains about whether early to bed and early to rise makes a man healthy, wealthy and wise (the Ben Franklin hypothesis), or healthy, wealthy and dead (the James Thurber hypothesis).

METHODS: As part of the Determinants of Myocardial Infarction Onset Study, we determined through personal interviews the bedtimes and wake times of 949 men admitted to hospital with acute myocardial infarction. Participants reported their educational attainment and zip code of residence, from which local median income was estimated. We followed participants for mortality for a mean of 3.7 years. We defined early-to-bed and early-to-rise respectively as a bedtime before 11 pm and wake time before 6:30 am.

RESULTS: Hours in bed were inversely associated with number of cups of coffee consumed (age-adjusted Spearman correlation coefficient r -0.07, p = 0.03). The mortality of early-to-bed, early-to-risers did not differ significantly from other groups. There was also no relation between bed habits and local income, nor with educational attainment.

INTERPRETATION: Our results refute both the Franklin and Thurber hypotheses. Early to bed and early to rise is not associated with health, wealth or wisdom.

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ABSTRACT #5

Neurology. 1997 Jan;48(1):103-7.

Ibuprofen or acetaminophen for the acute treatment of migraine in children: […]

Hämäläinen ML, Hoppu K, Valkeila E, Santavuori P.

Abstract

Efficacy of drugs for the acute treatment of migraine in children has not so far been studied in well controlled trials. We conducted a study to evaluate the efficacy of acetaminophen and ibuprofen. Eighty-eight children, aged 4.0 to 15.8 years, with migraine participated in a […] study. Three attacks per child were treated in random order with single oral doses of 15 mg/kg acetaminophen, 10 mg/kg ibuprofen, and placebo at home. The primary end point, reduction in severe or moderate headache (grade > or = 3 on a scale of 1 to 5) by at least two grades after 2 hours, was reached twice as often with acetaminophen and three times as often with ibuprofen as with placebo. Ibuprofen was twice as likely as acetaminophen to abort migraine within 2 hours. In the intent-to-treat analysis, children improved twice as often with ibuprofen and acetaminophen as with placebo. Both ibuprofen and acetaminophen are effective and economical treatments for severe or moderate migraine attacks in children. Ibuprofen gave the best relief.

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ABSTRACT #6

Cancer Causes Control. 2010 Jul;21(7):1139-45. Epub 2010 Mar 3.

Poverty and childhood cancer incidence in the United States.

Pan IJ, Daniels JL, Zhu K.

Abstract

This study examined socioeconomic differentials in cancer incidence rates during 2000-2005 among children aged 0-19 in the United States. The data on childhood cancers, which were classified by the International Classification of Childhood Cancer, Third Edition (ICCC-3), were obtained from the Surveillance, Epidemiology, and End Results program. The socioeconomic status of residential area at diagnosis was estimated by county-level poverty rate in Census 2000, i.e., percentage of persons in the county living below the national poverty thresholds. Counties were categorized as low-, medium-, and high-poverty areas when the poverty rates were <10, 10-19.99, and 20% or higher, respectively. The results showed that medium- and high-poverty counties had lower age-adjusted incidence rates than low-poverty counties for total childhood cancers combined, central nervous system neoplasms (ICCC group III), neuroblastoma (group IV), renal tumors (group VI), and other malignant epithelial neoplasms and malignant melanomas (group XI). When the data were stratified by race, these associations were observed among whites, but not blacks. For leukemia (group I), poor counties had higher incidence rates than affluent counties for whites, but lower rates for blacks. This […] provides perspective on area socioeconomic variations in childhood cancer incidence that warrants further research.

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ABSTRACT #7

BMC Public Health. 2009 Jul 20;9:252.

Does acute maternal stress in pregnancy affect infant health outcomes? Examination of […] infants born after the terrorist attacks of September 11, 2001.

Endara SM, Ryan MA, Sevick CJ, Conlin AM, Macera CA, Smith TC.

Abstract

BACKGROUND: Infants in utero during the terrorist attacks of September 11, 2001 may have been negatively affected by maternal stress. Studies to date have produced contradictory results.

METHODS: Data for this […] study were obtained from the Department of Defense Birth and Infant Health Registry and included up to 164,743 infants born to active-duty military families. Infants were considered exposed if they were in utero on September 11, 2001, while the referent group included infants gestating in the same period in the preceding and following year (2000 and 2002). We investigated the association of this acute stress during pregnancy with the infant health outcomes of male:female sex ratio, birth defects, preterm birth, and growth deficiencies in utero and in infancy.

RESULTS: No difference in sex ratio was observed between infants in utero in the first trimester of pregnancy on September 11, 2001 and infants in the referent population. Examination of the relationship between first-trimester exposure and birth defects also revealed no significant associations. In adjusted multivariable models, neither preterm birth nor growth deficiencies were significantly associated with the maternal exposure to the stress of September 11 during pregnancy.

CONCLUSION: The findings from this large population-based study suggest that women who were pregnant during the terrorist attacks of September 11, 2001 had no increased risk of adverse infant health outcomes.

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