The menstrual cycle is influenced by weekly and lunar rhythms.

OBJECTIVE: To study whether the menstrual cycle has a circaseptan (7 days) rhythm and whether it is associated with the lunar cycle (also defined as the synodic month, it is the cycle of the phases of the Moon as seen from Earth, averaging 29.5 days in length). DESIGN: Cross-sectional study. SUBJECTS: A total of 35,940 European and North American women aged 18-40 years. EXPOSURE: Data were collected in real-life conditions. INTERVENTION: No intervention was performed. MAIN OUTCOME MEASURE: The onset of menstruation was assessed in prospectively measured menstrual cycles (311,064 cycles) over 3 full years (2019-2021). Associations were calculated between the onset of menstruation and the day of the week, and between the onset of menstruation and the lunar phase. RESULTS: In this large data set, a circaseptan (7-day) rhythmicity of menstruation was observed, with a peak (acrophase) of menstrual onset on Thursdays and Fridays. This circaseptan rhythm was observed in every age group, in every phase of the lunar cycle, and in all seasons. This feature was most pronounced for cycle durations between 27 and 29 days. In winter, the circaseptan rhythm was found in cycles of 27-29 days, but not in other cycle lengths. A circalunar rhythm was also statistically significant, but not as clearly defined as the circaseptan rhythm. The peak (acrophase) of the circalunar rhythm of menstrual onset varied according to the season. In addition, there was a small but statistically significant interaction between the circaseptan rhythm and the lunar cycle. CONCLUSION: Although relatively small in amplitude, the weekly rhythm of menstruation was statistically significant. Menstruation occurs more often on Thursdays and Fridays than on other days of the week. This is particularly true for women whose cycles last between 27 and 29 days. Circalunar rhythmicity was also statistically significant. However, it is less pronounced than the weekly rhythm.

Distinct urinary progesterone metabolite profiles during the luteal phase.

OBJECTIVES: During normal menstrual cycles, serum levels of progesterone vary widely between cycles of same woman and between women. This study investigated the profiles of pregnanediol during the luteal phase. METHODS: Data stemmed from a previous multicenter prospective observational study and concerned 107 women (who contributed 326 menstrual cycles). The study analyzed changes in observed cervical mucus discharge, various hormones in first morning urine, and serum progesterone. Transvaginal ultrasonography and cervical mucus helped identifying the day of ovulation. Changes in pregnanediol glucuronide levels during the luteal phase were examined and classified according to the length of that phase, a location parameter, and a scale parameter. Associations between nine pregnanediol glucuronide profiles and other hormone profiles were examined. RESULTS: Low periovulatory pregnanediol glucuronide levels and low periovulatory luteinizing hormone levels were associated with delayed increases in pregnanediol glucuronide after ovulation. That 'delayed increase profile' was more frequently associated with cycles with prolonged high LH levels than in cycles with rapid pregnanediol glucuronide increases. A 'plateau-like profile' during the luteal phase was associated with longer cycles, cycles with higher estrone-3-glucuronide and pregnanediol glucuronide during the preovulatory phase, and cycles with higher periovulatory pregnanediol glucuronide levels. CONCLUSIONS: Distinct profiles of urinary progesterone levels are displayed during the luteal phase. These profiles relate to early hormone changes during the menstrual cycle. In everyday clinical practice, these findings provide further evidence for recommending progesterone test seven days after the mucus peak day. The search for other correlations and associations is underway.

Descriptive analysis of the relationship between progesterone and basal body temperature across the menstrual cycle.

OBJECTIVE: Describe the relationship between basal body temperature (BBT) and pregnanediol-3 alpha-glucuronide (PDG, the urine metabolite of progesterone) across the menstrual cycle. DESIGN: Observational study. SETTING: Study carried out from 1996 to 1997 in eight European family planning clinics. PARTICIPANT(S): One hundred and seven normally fertile and cycling women. MAIN OUTCOME MEASURE(S): BBT and PDG level on each day of 283 cycles and ultrasound determination of the day of ovulation. RESULT: (s): In comparison with previous end-of-cycle levels, decreases in PDG and BBT on the first day of menses were seen in nearly 90% and 80% of cycles, respectively. In a non-negligible percentage of cycles, luteolysis would continue during menses: between the second and the third day after menses, small but significant decreases in PDG and BBT were seen in 76% and 48% of cycles, respectively. During the peri-ovulatory phase, between the third and the second day before ovulation, PDG and BBT began to rise in 56% and 41% of cycles, respectively. There was a medium degree of correlation between PDG levels and BBT (r = 0.53; 7,279 days with available measurements). The relationship between PDG levels and BBT was linear at low PDG levels but BBT increased no longer when PDG levels continued to rise above a threshold of nearly 10 mcg/mg Cr. CONCLUSION: (s): PDG and BBT had parallel increases at low PDG rates but diverged at higher rates.

A Catholic Perspective: Triage Principles and Moral Distress in Pandemic Scarcity.

Striving to be faithful to the moral core of medicine and to spiritual, moral, and social teaching of the church, Catholic physicians see their role as an extension of the healing ministry of Jesus. When faced with a situation in which a large number of gravely ill people are seeking care, but optimal treatment such as ventilation in intensive care unit cannot be offered to all because of scarcity of resources, Catholic physicians recognize the need to consider the common good and to assign a priority to patients for whom such treatments would be most probably lifesaving. Making these evaluations, physicians will use only objective medical criteria regarding the benefits and risks to patients and will be mindful that all persons deserve equal respect for their dignity. Discrimination or prejudicial treatment against patients based on factors such as age, disability, race, gender, quality of life, and possible long-term survival cannot be morally justified. Triage process should incorporate respect for autonomy of both the patient and the professional and opportunity for an appeal of a triage decision. Other principles and values that will affect how a triage protocol is developed and applied are proportionality, equity, reciprocity, solidarity, subsidiarity, and transparency. The current coronavirus pandemic can provide valuable lessons and stimulus for reforms and renewal. SUMMARY: Catholic physicians strive to continue the healing ministry of Jesus Christ and be faithful to the moral core of medicine. In situations such as pandemic, the scarcity of personnel and technological resources create serious challenges and even moral distress. Church teachings on dignity, the common good and protection of the vulnerable help guide decisions based on public medical criteria and shared decision-making.

Pilot observational prospective cohort study on the use of a novel home-based urinary pregnanediol 3-glucuronide (PDG) test to confirm ovulation when used as adjunct to fertility awareness methods (FAMs) stage 1.

RATIONALE: Ovulation confirmation is a fundamental component of the evaluation of infertility. PURPOSE: To inform the design of a larger clinical trial to determine the effectiveness of a new home-based pregnanediol glucuronide (PDG) urine test to confirm ovulation when compared with the standard of serum progesterone. METHODS: In this observational prospective cohort study (single group assignment) in an urban setting (stage 1), a convenience sample of 25 women (aged 18-42 years) collected daily first morning urine for luteinisinghormone (LH), PDG and kept a daily record of their cervical mucus for one menstrual cycle. Serum progesterone levels were measured to confirm ovulation. Sensitivity and specificity were used as the main outcome measures. Estimation of number of ultrasound (US)-monitored cycles needed for a future study was done using an exact binomial CI approach. RESULTS: Recruitment over 3 months was achieved (n=28) primarily via natural fertility regulation social groups. With an attrition rate of 22%, specificity of the test was 100% for confirming ovulation. Sensitivity varied depending on whether a peak-fertility mucus day or a positive LH test was observed during the cycle (85%-88%). Fifty per cent of participants found the test results easy to determine. A total of 73 US-monitored cycles would be needed to offer a narrow CI between 95% and 100%. CONCLUSION: This is first study to clinically evaluate this test when used as adjunct to the fertility awareness methods. While this pilot study was not powered to validate or test efficacy, it helped to provide information on power, recruitment and retention, acceptability of the procedures and ease of its use by the participants. Given this test had a preliminary result of 100% specificity, further research with a larger clinical trial (stage 2) is recommended to both improve this technology and incorporate additional approaches to confirm ovulation. TRIAL REGISTRATION NUMBER: NCT03230084.

Corrigendum: Urinary Luteinizing Hormone Tests: Which Concentration Threshold Best Predicts Ovulation?

[This corrects the article DOI: 10.3389/fpubh.2017.00320.].

Hormonal Predictors of Abnormal Luteal Phases in Normally Cycling Women.

Objective: Explore potential relationships between preovulatory, periovulatory, and luteal-phase characteristics in normally cycling women. Design: Observational study. Setting: Eight European natural family planning clinics. Patient(s): Ninety-nine women contributing 266 menstrual cycles. Intervention(s): The participants collected first morning urine samples that were analyzed for estrone-3 glucuronide (E1G), pregnanediol-3- alpha-glucuronide (PDG), follicle stimulating hormone (FSH), and luteinizing hormone (LH). The participants underwent serial ovarian ultrasound examinations. Main Outcome Measure(s): Four outcome measures were analyzed: short luteal phase, low mid-luteal phase PDG level (mPDG), normal then low luteal PDG level, low then normal luteal PDG level. Results: A long preovulatory phase was a predictor of short luteal phase, with or without adjustment for other variables. A high periovulatory PDG level was a predictor for short luteal phase as well as normal then low luteal PDG level. A low periovulatory PDG level predicted low mPDG and low then normal luteal PDG level, with or without adjustment for other variables. A small maximum follicle predicted normal then low luteal PDG level, with or without adjustment for other variables. The relationship between small maximum follicle size and short luteal phase or small maximum follicle size and low mPDG was no longer present when the regression was adjusted for certain characteristics. A younger age at menarche and a high body mass index were both predictors of low mPDG. Conclusion: Luteal phase abnormalities exist over a spectrum where some ovulation disorders may exist as deviations from the normal ovulatory process.This study confirms the negative impact of a small follicle size on the quality of the luteal phase. The occurrence of normal then low luteal PDG level is confirmed as a potential sign of luteal phase abnormality.

A Quadriparametric Model to Describe the Diversity of Waves Applied to Hormonal Data.

BACKGROUND: Even in normally cycling women, hormone level shapes may widely vary between cycles and between women. Over decades, finding ways to characterize and compare cycle hormone waves was difficult and most solutions, in particular polynomials or splines, do not correspond to physiologically meaningful parameters. OBJECTIVE: We present an original concept to characterize most hormone waves with only two parameters. METHODS: The modelling attempt considered pregnanediol-3-alpha-glucuronide (PDG) and luteinising hormone (LH) levels in 266 cycles (with ultrasound-identified ovulation day) in 99 normally fertile women aged 18 to 45. The study searched for a convenient wave description process and carried out an extended search for the best fitting density distribution. RESULTS: The highly flexible beta-binomial distribution offered the best fit of most hormone waves and required only two readily available and understandable wave parameters: location and scale. In bell-shaped waves (e.g., PDG curves), early peaks may be fitted with a low location parameter and a low scale parameter; plateau shapes are obtained with higher scale parameters. I-shaped, J-shaped, and U-shaped waves (sometimes the shapes of LH curves) may be fitted with high scale parameter and, respectively, low, high, and medium location parameter. These location and scale parameters will be later correlated with feminine physiological events. CONCLUSION: Our results demonstrate that, with unimodal waves, complex methods (e.g., functional mixed effects models using smoothing splines, second-order growth mixture models, or functional principal-component- based methods) may be avoided. The use, application, and, especially, result interpretation of four-parameter analyses might be advantageous within the context of feminine physiological events.

Urinary Luteinizing Hormone Tests: Which Concentration Threshold Best Predicts Ovulation?

OBJECTIVE: To study the best possible luteinizing hormone (LH) threshold to predict ovulation within the 24, 48, and 72 h. DESIGN: Observational study. SETTING: Multicenter collaborative study. PATIENTS: A total of 107 women. INTERVENTIONS: Women collected daily first morning urine for hormonal assessment and underwent serial ovarian ultrasound. This is a secondary analysis of 283 cycles. MAIN OUTCOME MEASURES: The sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios were estimated for varying ranges of LH thresholds. Receiver operating characteristic curves and cost-benefit ratios were used to estimate the best thresholds to predict ovulation. RESULTS: The best scenario to predict ovulation at random was within 24 h after the first single positive test. The false-positive rate was found to increase as (1) the cycle progressed or (2) two or three consecutive tests were used, or (3) ovulation was predicted within 48 or 72 h. Testing earlier in the cycle increases the predictive value of the test. The ideal thresholds to predict ovulation ranged between 25 and 30 mIU/ml with a PPV (50-60%), NPV (98%), LR+ (20-30), and LR- (0.5). At least, one day with LH ≥25 mIU/ml followed by three negatives (LH <25) occurred before ovulation in 31% of all cycles. When used throughout the cycle and evaluated together, peak-fertility type mucus with a positive LH test ≥25 mIU/ml provides a higher specificity than either mucus or LH testing alone (97-99 vs. 77-95 vs. 91%, respectively). CONCLUSION: We identified that beginning LH testing earlier in the cycle (day 7) with a threshold of 25-30 mIU/ml may present the best predictive value for ovulation within 24 h. However, prediction by LH testing alone may be affected negatively by several confounding factors so LH testing alone should not be used to define the end of the fertile window. Complementary markers should be further investigated to predict ovulation and identify the fertile window. The use of the peak cervical mucus along with an LH test may provide a higher specificity and predictive value than either of them alone. We recommend that manufacturers disclose their tests' threshold to the public.

Characterization of hormonal profiles during the luteal phase in regularly menstruating women.

OBJECTIVE: To characterize the variability of hormonal profiles during the luteal phase in normal cycles. DESIGN: Observational study. SETTING: Not applicable. PATIENT(S): Ninety-nine women contributing 266 menstrual cycles. INTERVENTION(S): The women collected first morning urine samples that were analyzed for estrone-3-glucuronide, pregnanediol-3-alpha-glucuronide (PDG), FSH, and LH. The women had serum P tests (twice per cycle) and underwent ultrasonography to identify the day of ovulation. MAIN OUTCOME MEASURE(S): The luteal phase was divided into three parts: the early luteal phase with increasing PDG (luteinization), the midluteal phase with PDG ≥10 µg/mg Cr (progestation), and the late luteal phase (luteolysis) when PDG fell below 10 µg/mg Cr. RESULT(S): Long luteal phases begin with long luteinization processes. The early luteal phase is marked by low PDG and high LH levels. Long luteinization phases were correlated with low E1G and low PDG levels at day 3. The length of the early luteal phase is highly variable between cycles of the same woman. The duration and hormonal levels during the rest of the luteal phase were less correlated with other characteristics of the cycle. CONCLUSION(S): The study showed the presence of a prolonged pituitary activity during the luteinization process, which seems to be modulated by an interaction between P and LH. This supports a luteal phase model with three distinct processes: the first is a modulated luteinization process, whereas the second and the third are relatively less modulated processes of progestation and luteolysis.

Self-identification of the clinical fertile window and the ovulation period.

OBJECTIVE: To assess the sensitivity and specificity of the self-identified fertile window. DESIGN: Observational study. SETTING: Not applicable. PATIENT(S): A total of 107 women. INTERVENTION(S): Women recorded cervical mucus observation and basal body temperature daily while undergoing daily ovarian ultrasound. MAIN OUTCOME MEASURE(S): The biological fertile window, defined as the 6 days up to and including the day of ovulation; and the 2-day ovulation window, defined as the day before and the day of ovulation. RESULT(S): The self-identification of the biological fertile window by the observation of any type of cervical mucus provides 100% sensitivity but poor specificity, yielding a clinical fertile window of 11 days. However, the identification of the biological fertile window by peak mucus (defined as clear, slippery, or stretchy mucus related to estrogen) yielded 96% sensitivity and improved specificity. The appearance of the peak mucus preceded the biological fertile window in less than 10% of the cycles. Likewise, this type of mucus identified the ovulation window with 88% sensitivity. CONCLUSION(S): These results suggest that, when perceived accurately, more accurate clinical self-detection of the fertile window can be obtained by identification of peak mucus. This may improve efforts to focus intercourse in the fertile phase for couples with fertility concerns.

Use of ovulation predictor kits as adjuncts when using fertility awareness methods (FAMs): a pilot study.

PURPOSE: Difficult clinical signs such as confusing cervical mucus or erratic basal body temperature can make the use of fertility awareness methods (FAMs) difficult in some cases. The goal of this study was to assess the feasibility of using a cheap urinary luteinizing hormone (LH)-surge identification kit as an adjunct to identify the infertile phase after ovulation when facing these scenarios. METHODS: The study used a block-allocation, crossover, 2-arm methodology (LH kit/FAM vs FAM only). Comparison of the 2 arms was done with regard to the accuracy of identification (yes/no) of the luteal phase in each cycle as confirmed by serum progesterone concentrations. RESULTS: We recruited 23 Canadian women currently using FAM, aged 18 to 48 years, who have had menstrual cycles 25 to 35 days long for the past 3 months and perceive themselves to have difficulty with identifying the infertile phase after ovulation. LH kits identified 100% of the luteal phases, whereas FAM indentified 87% (statistically significant). In those identified cycles, LH kits provided a mean of 10.3 days of infertility, and FAM only provided 10 days of infertility (not statistically significant). CONCLUSIONS: Among this population, LH kits may offer an adjunct for women who may wish to have an additional double-check. However, there are still clinical circumstances when even an LH kit does not provide confirmation. More research in this area is encouraged.

Characterization of follicle stimulating hormone profiles in normal ovulating women.

OBJECTIVE: To describe FSH profile variants. DESIGN: Observational study. SETTING: Multicenter collaborative study. PATIENT(S): A total of 107 women. INTERVENTION(S): Women collected daily first morning urine and underwent serial ovarian ultrasound. MAIN OUTCOME MEASURE(S) FSH RESULT(S): The individual FSH cyclic profiles demonstrated a significant departure from the currently accepted model. A decline in FSH levels at the end of the follicular phase was observed in only 42% of cycles. The absence of this decline was significantly associated with a shorter luteal phase and higher pregnanediol-3α-glucuronide, FSH, and LH levels at the time of ovulation. In 34% of the cycles, significant FSH variability was observed throughout the follicular phase; this variability was associated with higher body mass index and lower overall FSH and LH levels throughout the cycle. The FSH peak occurs on average 2 hours before ovulation. The FSH peak duration was shorter than the LH peak. CONCLUSION(S): These results suggest that average FSH profiles may not reflect the more complex dynamics of daily hormonal variations in the menstrual cycle. It is possible that discrepancies between the average normal FSH profile and the individual day-to-day variants can be used to detect abnormalities.

Screening for drug and alcohol use disorders and their association with HIV-related sexual risk behaviors among men who have sex with men in Peru.

BACKGROUND: Peru's HIV epidemic is concentrated among men who have sex with men (MSM). The contribution of alcohol use disorders (AUDs) to known high-risk behaviors associated with HIV transmission in this context has not been well characterized. METHODS: Between June and October 2011, 5,148 sexually active MSM were recruited using convenience sampling in five cities to participate in a cross-sectional bio-behavioral survey. Five high-risk sexual criteria previously associated with incident HIV infection in this setting were selected a priori as the dependent outcomes. Screening for AUDs used the validated Alcohol Use Disorders Identification Test (AUDIT) and AUDS were stratified by severity. Unadjusted and adjusted odds ratios (AOR) were computed to establish the independent correlates of the five dependent outcomes. RESULTS: The majority (62.8%) of participants met screening criteria for having an AUD, which were independently correlated with each of the following high-risk sexual risk behaviors in the previous 6 months: 1) >5 sexual partners [AOR = 1.76; (1.54-2.02)]; 2) sex with an HIV-infected partner [AOR = 1.29; (1.03-1.62)]; 3) having a sexually transmitted infection [AOR = 1.38; (1.13-1.68)]; 4) being a sex worker [AOR = 1.61; (1.40-1.87)]; and 5) unprotected sex during last encounter [AOR = 1.22; (1.09-1.38)]. Recent drug use was also correlated with having >5 sexual partners [AOR = 1.42 (1.19-1.71)], sex work [AOR = 1.97 (1.63-2.39)] and unprotected sex during last encounter [AOR = 1.31 (1.11-1.54)]. For each dependent variable, the association with AUDs significantly increased with increasing AUD severity. CONCLUSIONS: AUDs are highly prevalent among MSM in Peru and are associated with increased HIV risk-taking behaviors that are associated with HIV transmission. Strategies that target problematic drinking such as medication-assisted therapy, behavioral counseling and structural interventions could potentially reduce risky behaviors and ultimately reduce HIV transmission among MSM in Peru.

The Montreal Cognitive Assessment (MoCA) in geriatric rehabilitation: psychometric properties and association with rehabilitation outcomes.

BACKGROUND: Cognitive status has been reported to be an important predictor of rehabilitation outcome. The Montreal Cognitive Assessment (MoCA) was designed to overcome some of the limitations of established cognitive screening tools such as the Mini-Mental State Examination (MMSE). The purpose of this study is to evaluate the psychometric characteristics of the MoCA as a screening tool in a geriatric rehabilitation program and its ability to predict rehabilitation outcome. METHODS: Forty-seven geriatric rehabilitation program patients participated in the study. Assessments of each patient's functional (Functional Independence Measure) and cognitive status (MMSE and MoCA) were performed. Information on discharge destinations were obtained and rehabilitation efficacy and efficiency scores were calculated. RESULTS: Significant correlations were found between the MoCA and other cognitive status measures. Cognitive status at admission and successful rehabilitation were also associated. Defining rehabilitation success on the basis of relative functional efficacy (an indicator that includes the patient's potential for improvement), the sensitivity and specificity of the MoCA were 80% and 30% respectively. The attention subscale of the MoCA was also uniquely predictive of rehabilitation success. The attention subscale (cutoff 5/6) of the MoCA had a sensitivity of 40% and specificity of 90%, as did the MMSE. CONCLUSIONS: As a cognitive screening tool, the MoCA appears to have acceptable psychometric properties. Results suggest that the MoCA can have a considerable advantage over the MMSE in sensitivity and equivalence in specificity using both total and attention scale scores. The MoCA may be a more useful measure for detecting cognitive impairment and predicting rehabilitation outcome in this population.

Tendencia de la visibilidad y análisis de citas recibidas del Boletín Epidemiológico (Lima) por revistas biomédicas (1991-2011) / Visibility trend and analysis of citations of Boletín Epidemiológico (Lima) by biomedical journals (1991-2011)

No se conocen los indicadores bibliométricos de la información producida por el sistema de vigilancia del Perú. El objetivo de esta comunicación fue conocer la tendencia de las descargas y el número total de citas recibidas del Boletín Epidemiológico (Lima) por revistas biomédicas (Enero 1991 - agosto 2011). Métodos: La visibilidad fue evaluada mediante las estadísticas de descarga disponible en www.dgr.gob.pe. Las citas se buscaron electrónicamente utilizándo los títulos y acrónimos del Boletín Epidemiológico (Lima) en Google Scholar. Adicionalmente, se revisaron manualmente la sección de referencias de seis revistas en formato físico publicados entre el 2000 y el 2004, y electrónicamente, de 12 revistas biomédicas indizadas publicadas entre enero de 1991 y agosto de 2011. Resultados: En el periodo de estudio, el Boletín Epidemiológico (Lima) recibió 89 citas por 13 revistas, cuatro de las cuales eran internacionales. La Revista Peruana de Medicina Experimental y Salud Pública le otorgó 35/89 (39.3 %) citas y la Revista Peruana de Epidemiología, 20/89 (22.4 %) citas. Los temas más citados fueron malaria con 15/89 (16.8 %) y dengue con 14/89 (15.7 %) citas. La secciones más citadas del Boletín Epidemiológico (Lima) fueron situación epidemiológica que recibió 68/89 (76.4 %) citas y 10/89 (11.2 %) citas que recibió los editoriales. En 2006, se contabilizaron 23178 descargas con 469 en promedio de descargas semanales y el año 2007, se contabilizó 21441 descargas con 412 en promedio de descargas semanales. Conclusiones: Existe un bajo índice de descargas, pero con una tendencia histórica al incremento del total de citas recibidas hasta el 2009, que sugiere la utilidad de la información publicada por el Boletín Epidemiológico (Lima).

There are not known bibliometric indicators of the information produced by the surveillance system in Peru. Aim: to determine the trend of downloads and the total number of citations of Boletín Epidemiológico (Lima) for biomedical journals (January 1991 - August 2011). Methods: visibility was evaluated by download statistics available at www.dge.gob.pe. Citations were searched electronically using the titles and acronyms of Boletín Epidemiológico (Lima) on Google Scholar. Additionally, we manually reviewed the reference section of 6 journals printed between 2000 and 2004, and 12 on-line journals, indexed and published between January 1991 and August 2011. Results: During the study period, Boletín Epidemiológico (Lima) was cited 89 times by 13 journals, 4 of which were international. Boletín Epidemiológico (Lima) was cited in 35 (39.3%) articles by Revista Peruana de Medicina Experimental y Salud Pública and in 20 (22.4%) articles by Revista Peruana de Epidemiología. The subjects most cited were malaria with 15 (16.8%) and dengue with 14 (15.7%) citations. The most cited sections of Boletín Epidemiológico (Lima) were epidemiological situation with 68 (76.4%) citations and editorial with 10 (11.2%) citations. During 2006, there were 23 178 downloads with an average of 469 weekly downloads and during 2007 21 441 downloads with 412 downloads per week on average. Conclusions: There is a low rate of downloads, but with a historical tendency to increase until 2009, suggesting the usefulness of the information published by Boletín Epidemiológico (Lima).