Change in Impact Factors of Public Health journals

While the most recent year's public health and epidemiology journal impact factor is informative, it is also very helpful to know to long term temporal trends in journals to assess a journal increase or decline.

Recently there was a study ("Time trends in the impact factor of Public Health journals" BMC Public Health. 2005; 5: 24) that examined the slope and an index of annual change of various public health and epidemiology journals' impact factors. Below is a tabulation (available open-access via PubMedCentral).

Journals ranked in descending order, by index of annual change (IAC).

Title	IAC	IF(2003)	mean	p-value
TOBACC. CONTROL	0.509	3.164	2.052	0.181
J. WOMEN. HEALTH. GEN. B	0.388	1.561	0.928	0.007
J. URBAN. HEALTH	0.316	1.286	0.723	0.002
INT. J. HYG. ENVIR. HEAL	0.302	1.085	0.822	0.142
EPIDEMIOLOGY	0.250	4.220	3.093	0.000
DRUG. SAFETY	0.238	2.971	2.059	0.000
AM. J. PREV. MED	0.232	3.256	1.440	0.000
ANNU. REV. PUBL. HEALTH	0.225	5.179	3.158	0.010
ENVIRON. HEALTH. PERSP	0.220	3.038	2.192	0.000
ANN. AGR. ENV. MED	0.216	0.827	0.590	0.065
CANCER. EPIDEMI. BIOMAR	0.214	4.720	3.475	0.001
SCAN. J. PUBLIC. HEALT	0.207	1.018	0.714	0.044
TROP. MED. INT. HEALTH	0.181	2.156	1.477	0.003
AIHAJ	0.180	0.601	0.449	0.166
SOZ. PREVENTIV. MED	0.170	0.750	0.525	0.013
ANN. EPIDEMIOL	0.141	2.345	1.995	0.001
PSYCHIATR. SERV	0.138	2.274	1.658	0.004
PAEDIATR. PERINAT. EP	0.132	1.673	1.176	0.005
INT. J. EPIDEMIOL	0.125	3.289	1.820	0.001
J. EXPO. ANAL. ENV. EPID	0.124	1.263	1.033	0.001
B. WORLD. HEALTH. ORGAN	0.115	2.442	1.838	0.001
TOXICOL. IND. HEALTH	0.106	0.508	1.051	0.206
MED. CARE	0.105	3.152	2.379	0.004
PATIENT. EDUC. COUNS	0.103	1.130	0.774	0.001
OCCUP. ENVIRON. MED	0.100	1.847	1.755	0.013
AM. J. EPIDEMIOL	0.099	4.486	3.788	0.000
NEUROEPIDEMIOLOGY	0.095	1.762	1.411	0.001
INT. J. ENVIRON. HEAL. R	0.094	0.588	0.419	0.088
CANCER. CAUSE. CONTROL	0.087	2.726	2.623	0.061
INDOOR. BUILT. ENVIRON	0.085	0.525	0.496	0.542
J. ADOLESCENT. HEALTH	0.082	1.674	1.361	0.000
INFECT. CONT. HOSP. EP	0.081	1.951	2.074	0.035
J. OCCUP. ENVIRON. MED	0.081	1.472	1.349	0.121
AM. J. PUBLIC. HEALTH	0.076	3.363	3.057	0.010
AVIAT. SPACE. ENVIR. MD	0.075	0.946	0.681	0.007
J. EPIDEMIOL. COMMUN. H	0.075	2.332	1.679	0.003
SCAN. J. WORK. ENV. HEA	0.075	1.816	1.433	0.001
ANN. OCCUP. HYG	0.070	1.357	1.041	0.002
COMUNITY. DENT. ORAL	0.069	1.100	0.976	0.002
J. CLIN. EPIDEMIOL	0.065	2.227	1.872	0.001
TR. ROY. SOC. TROP. MED. H	0.064	2.114	1.553	0.001
ENVIRON. RES	0.058	1.452	1.390	0.068
J. AEROSOL. MED	0.056	1.459	0.818	0.006
QUAL. HEALTH. CARE	0.056	1.466	1.232	0.221
ANN. TROP. MED. PARASIT	0.052	1.010	0.837	0.000
AM. J. IND. MED	0.049	1.542	1.256	0.001
OCCUP. MED. OXFORD	0.041	0.693	0.464	0.010
J. SCHOOL. HEALTH	0.039	0.868	0.688	0.185
FLUORIDE	0.034	0.907	0.560	0.018
J. PUBLIC. HEALTH. MED	0.032	0.973	0.805	0.014
STAT. MED	0.030	1.134	1.238	0.094
ENVIRON. GEOCHEM. HLTH	0.027	0.565	0.369	0.082
ANN. HUM. BIOL	0.026	0.885	0.787	0.001
INT. ARCH. OCC. ENV. HEA	0.026	1.388	1.086	0.072
PUBLIC. HEALTH	0.025	0.697	0.522	0.010
PUBLIC. HEALTH. REP	0.025	1.139	1.012	0.192
REV. EPIDEMIOL. SANTE	0.024	0.485	0.401	0.003
EPIDEMIOL. INFECT	0.023	1.509	1.594	0.199
EUR. J. EPIDEMIOL	0.022	0.972	0.676	0.080
TROP. DOCT	0.022	0.347	0.326	0.089
J. ENVIRON. HEALTH	0.021	0.341	0.228	0.007
AM. J. TROP. MED. HYG	0.019	2.105	1.950	0.058
GENET. EPIDEMIOL	0.018	2.265	1.681	0.544
IND. HEALTH	0.015	0.474	0.497	0.262
INT. J. TECHNOL. ASSESS	0.013	0.754	0.922	0.686
PREV. MED	0.013	1.889	1.540	0.568
HEALTH. PHYS	0.012	0.777	0.865	0.385
EUR. J. PUBLIC. HEALTH	0.002	1.281	1.044	0.983
J. PUBLIC. HEALTH. DENT	-0.010	1.000	0.787	0.568
WILD. ENVIRON. MED	-0.019	0.280	0.339	0.822
J. PUBLIC. HEALTH. POL	-0.023	0.314	0.615	0.675
J. MED. SCREEN	-0.033	1.867	1.815	0.696
J. ENVIRON. SCI. HEAL. B	-0.034	0.758	0.718	0.131
BIOMED. ENVIRON. SCI	-0.036	0.609	0.557	0.596
J. OCCUP. HEALTH	-0.040	1.047	1.049	0.445
ARCH. ENVIRON. HEALTH	-0.054	0.878	1.391	0.028
B. SOC. PATHOL. EXOT	-0.092	0.183	0.262	0.154
PALLIATIVE. MED	-0.103	1.185	1.627	0.060
QUAL. LIFE. RES	-0.171	2.000	2.089	0.149
EPIDEMIOL. REV	-0.175	3.306	3.203	0.076

METHODS:

Study selected 80 journals that: were included in the "Public, Environmental and Occupational Health" category of the hard copy version of the Journal Citation Reports (JCR) from 1992 through 2003; were listed for a minimum period of 3 consecutive years; and had IFs in the JCR for 2003. Study consulted the 2003 JCR-IFs via the ISI Web of Knowledge. The impact factor is one of the quantitative tools provided by JCR for ranking, evaluating, categorizing, and comparing journals. The annual impact factor of a journal is calculated by dividing the number of current year citations to the source items published in that journal during the previous two years. Impact factor time trends were assessed using a linear regression model, in which the dependent variable was IF and the independent variable, the year. The slope of the model (index of annual change-IAC) and its statistical significance were taken as the indicator of year-to-year variation.

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Worldwide Readership of Epidemiologic Inquiry

To new visitors and our dedicated community of readers, we are pleased to report that Epidemiologic Inquiry has again consistently grown in the past few months. An impressive geographic distribution of readers from not only North America and Europe, but also from Australia, East Asia, South Asia, Middle East, and others corners of the globe! (see map below)

We now also offer our latest EPIDEMIOLOGY FORUM as a way to further foster an online epidemiology community to share questions, debates, and collaborations. We encourage you to bookmark our homepage to regularly visit and explore the latest information and discussions in the weblog and forum.

Thank you for your continued readership.

Sincerely,
The Editorial Board


Figure. Worldwide Geographic Distribution of Visitors
(updated November 20, 2006) (click to enlarge)

Coverpage of The Lancet: ABC of HIV Prevention

An interesting billboard featured on the homepage of The Lancet this week...












...if only HIV and AIDS prevention is as easy as 1-2-3.

Useful CDC email listservs

Many epidemiologists and public health practioners find Centers for Disease Control email distribution lists, or listservs, useful in following latest the information regarding a particular public health realm.

Here the one central webpage for subscribing to and joining the primary CDC listservs...
http://www.cdc.gov/subscribe.html

The National Center for Health Statistics (NCHS) of the CDC also has a separate set of listservs that provide email announcements regarding updates, releases, or technical assistance related to NHANES and other health statistics databases and resources...
http://www.cdc.gov/nchs/products/elecannounc/nchslists.htm

New 2006 edition of Health United States released by CDC

The annual "Health, United States" reference book for 2006 was just released yesterday by the CDC. Additionally, each year also highlights a certain theme in detail, this year being "pain". Below is a bulleted summary of the latest 2006 statistics for pain and general health.

===========================================

Health United States, 2006
released today 11/17/2006
Centers for Disease Control and Prevention's (CDC), National Center for Health Statistics

New Report Finds Pain Affects Millions of Americans

"We chose to focus on pain in this report because it is rarely discussed as a condition in and of itself - it is mostly viewed as a byproduct of another condition," said lead study author Amy Bernstein. "We also chose this topic because the associated costs of pain are posing a great burden on the health care system, and because there are great disparities among different population groups in terms of who suffer from pain."

• -One in four U.S. adults say they suffered a day-long bout of pain in the past month,
  one in 10 say the pain lasted a year or more
• -Hospitalization rates for knee replacement procedures rose nearly 90 percent between 1992-93 and 2003-04 among those 65 and older
• -One-fifth of adults 65 years and older said they had experienced pain in the past month that persisted for more than 24 hours.
• -Almost three-fifths of adults 65 and older with pain said it had lasted for one year or more.
• -More than one-quarter of adults interviewed said they had experienced low back pain in the past three months.
• -Fifteen percent of adults experienced migraine or severe headache in the past three months.
• -Adults ages 18-44 were almost three times as likely as adults 65 and older to report migraines or severe headaches.
• -Reports of severe joint pain increased with age, and women reported severely painful joints more often than men (10 percent versus 7 percent).
• -Between the periods 1988-94 and 1999-2002, the percentage of adults who took a narcotic drug to alleviate pain in the past month rose from 3.2 percent to 4.2 percent.
• -The United States spent an average of $6,280 per person on health care in 2004.
• -Seven percent of adults under 65 said they passed up getting needed care in the past 12 months due to costs.

The report also notes a number of other significant health findings:

• -Life expectancy at birth reached a record 77.9 years in 2004, up from 77.5 in 2003 and from 75.4 in 1990.
• -Since 1990, the gap in life expectancy between men and women has narrowed from seven to just over five (5.2) years.
• -At birth, life expectancy for females is just over 80 years and nearly 75 for males. The gap in life expectancy between white and black Americans also has narrowed from seven years in 1990 to five years in 2004.
• -Infant mortality fell to 6.8 deaths per 1,000 live births in 2004, down from 6.9 deaths per 1,000 live births in 2003.
• -Heart disease remains the leading killer, but deaths from heart disease fell 16 percent between 2000 and 2004
• -Deaths from cancer - the No. 2 killer - dropped 8 percent between 2000 and 2004
• -The age-adjusted death rate for heart disease was 217 deaths per 100,000 in 2004
• -The age-adjusted death rate for cancer the rate was 186 per 100,000 in 2004
• -Diabetes poses a growing threat, especially among older adults. Eleven percent of adults aged 40-59 years, and 23 percent of those 60 and older have diabetes.

New Smokefree States 11/2006

In the continuing public health campaign against tobacco, several additional states have now gone "smokefree" via referendums passed by voters after the recent November 2006 U.S. midterm elections. (click image below to enlarge)

Worldwide, the entire countries of Ireland, Italy, Scotland, England, Norway, Sweden, New Zealand, Uganda, Malta, Uruguay, Hong Kong, and Bhutan have enacted comprehensive smokefree workplace legislation, including smokefree restaurants and bars.

The list is now longer than just a few months ago, however, much progress has yet to be made.



















Source: www.smokefree.net

Agreement of Observational and Randomized Trial Results

Critics of epidemiology often claim that the results of observational studies and randomized trials often conflict. However, besides obvious settings in which randomized trials are fantastically ethical, such as randomizing patients in clinical trials to adverse toxins, radiation, cigarette smoking, or no parachute use to prevent death and major trauma related to gravitational challenge, how true is the claim, on a more evidence-based scientific standard, that observational studies and trials too often conflict?

Fortunately, there were several prominent analyses in the NEJM and BMJ exactly focused on this question. In a BMJ paper in 2001 by Ioannidis et al. , the authors performed an analysis directly comparing the odds ratios of 25 separately clinical investigations in which both observational and randomized studies were conducted and found that the correlation between the odds ratio of randomised trials and the odds ratio of observational designs is actually 0.84, P less than 0.001. See Figure 1 below. This article notably reviewed 2 prominent studies in the NEJM, which both found that results from observational epidemiologic studies have been highly consistent with results from randomized trials-- see Figure 2, and references 2 and 3 below for more information. Indeed this body of evidence quite strongly supports the notion that prospective observational epidemiology is as reliable as randomized trials.

Furthermore, even in the field of digestive surgery, with relatively few large and long term cohorts, it was found in a review by Shikata et al. 2006 that only 4 of 16 observational studies differed significantly from randomized trials, with 75% of observational studies still in agreement with surgical trials, which often cannot be perfectly double-blinded themselves. In addition, there was also significant between-study heterogeneity in the body of these surgical randomized trials, suggesting the minor inconsistencies between study designs may be due to effect modification by underlying patient characteristics rather than bias from residual confounding in observational studies.

On the other hand, critics have frequently argued that epidemiologists got the answer wrong on the effects of estrogen, particularly as the large WHI estrogen trial was published after the 2001 study by Ioannidis et al. However, Grodstein et al.'s NEJM review article comparing the summary evidence about estrogen in prospective observational vs. randomized trials again clearly indicates strong agreement of results.

Notably, observational studies of estrogen therapy found nearly identical or similar associations for: 1. breast cancer, 2. colorectal cancer, 3. hip fracture, 4. stroke, 5. pulmonary embolism-- with the exception of only coronary heart disease, see Figure 2 summary below from Grodstein et al. However, the previous review of the estrogen and CHD issue discusses the likely explanation of the divergent results between observational studies and the WHI trial.

Although there are indeed some other observational studies that conflict with trials, most of such observational studies were either a) ecologic in design- the weakest study design of all and not considered rigorous, b) retrospective case-control design, which has many major limitations regarding recall and selection biases, c) were small in study size and thus more likely to exhibit false-positive results, and d) not carefully controlled for a wide range of confounders. In contrast, large and long term prospective cohort studies with >20 years of followup have generally provided the most reliable and reproducible results.

As we can see the prominent examples reviewed in the several BMJ and NEJM articles, the majority of the evidence indicates that observational epidemiology and clinical trials indeed provide generally consistent results.

[We encourage interested readers to subscribe for updates on new articles]

(click images to enlarge figures)

Figure 1. (from Ioannidis et al.)















Figure 2. (Benson and Hartz)















Figure 3. (from Grodstein et al.)











References:

1. Ioannidis JP, Haidich AB, Lau J. Any casualties in the clash of randomised and observational evidence? BMJ. 2001 Apr 14;322(7291):879-80.

2. Benson K, Hartz AJ. A comparison of observational studies and randomized, controlled trials. N Engl J Med 2000; 342: 1878-1886.

3. Concato J, Shah N, Horwitz RI. Randomized, controlled trials, observational studies, and the hierarchy of research designs. N Engl J Med 2000; 342: 1887-1892.

4. Shikata S, Nakayama T, Noguchi Y, Taji Y, Yamagishi H. Comparison of Effects in Randomized Controlled Trials With Observational Studies in Digestive Surgery. Ann Surg. 2006 Nov;244(5):668-676.

5. Grodstein F, Clarkson TB, Manson JE. Understanding the divergent data on postmenopausal hormone therapy. N Engl J Med 2003;348:645-650.

NIH budget cuts for 2006

Below are the planned NIH budget cuts for fiscal year 2006 (source: NIH):

• Congressional budget cut of 1 percent across-the-board cut for all non-emergency discretionary programs for FY 2006 reduced NIH's budget appropriation by $286 million.
• NIH will reduce all non-competing research project grant (RPG) awards by 2.35 percent
• NIH will maintain the average cost of competing RPGs at FY 2005 levels.
• Targeted overall success rate of 19.5 percent, approximately (compared to 22.3 percent in FY 2005).
• Expects to fund more than 38,300 competing and non-competing RPGs in 2006. When compared to FY 2005, this represents a decrease of about 570 RPGs or 1.5 percent.
• Existing grants may incur a percentage reduction in funding allocation, per rules of each individual NIH agency.

For an additional analysis of NIH grant success rates for individual institutes in 2005 and analysis of change since 2004, visit here http://www.epidemiologic.org/2006/10/nih-grant-success-rates-and-change.html.

Also, a list of NIH institutes that report payline percentiles of funded grants is available here (other institutes use a different payline determination method): http://www.epidemiologic.org/pics/NIH-payline.JPG

--> The congressional budget request for the NIH is $28.4 billion in FY 2007, the same as the FY2006 level for the agency.