ArticleCMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne2015
Seasonal effects on the occurrence of nocturnal leg cramps: a prospective cohort study.
Article in CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne, 2015. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 14 papers, 2 of them syntheses that pooled it.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
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Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
14 citing papers in PubMed, 2 syntheses or guidelines pooled it, 28 citations in OpenAlex.
- Assessing the Methods, Tools, and Statistical Approaches in Google Trends Research: Systematic Review.Journal of medical Internet research · 2018Pooled it
- Criteria in diagnosing nocturnal leg cramps: a systematic review.BMC family practice · 2017Pooled it
- Has National Colorectal Cancer Awareness Month increased endoscopy screening rates and public interest in colorectal cancer?Surgical endoscopy · 2021Article
- Quality of warfarin management in primary care: Determining the stability of international normalized ratios using a nationally representative prospective cohort.Canadian family physician Medecin de famille canadien · 2019Article
- Seasonality of bruxism: evidence from Google Trends.Sleep & breathing = Schlaf & Atmung · 2019Observational
- Seasonal variation in the internet searches for gout: an ecological study.Clinical rheumatology · 2019Observational
- Association Between Alcohol Consumption and Nocturnal Leg Cramps in Patients Over 60 Years Old: A Case-Control Study.Annals of family medicine · 2018Article
- Seasonality of cellulitis: evidence from Google Trends.Infection and drug resistance · 2018Article
- Prevalence of cramps in patients over the age of 60 in primary care : a cross sectional study.BMC family practice · 2016Observational
- Seasonality of Ankle Swelling: Population Symptom Reporting Using Google Trends.Annals of family medicine · 2016Article
- Harnessing big data for health.CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne · 2016Article
- Quinine and leg cramps.CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne · 2015Article
- Quinine: not a safe drug for treating nocturnal leg cramps.CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne · 2015Article
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Authors and funding
5 authors at 1 institution in 1 country.
Funding
Abstract
backgroundIt has been anecdotally reported that nocturnal leg cramps in pregnant women are worse in summer. We analyzed population-level data to determine whether the symptom burden of nocturnal leg cramps is seasonal in the general population.
methodsWe examined time-series data for 2 independent measures of the symptom burden of leg cramps: (a) new quinine prescriptions (reflecting new or escalating treatment of leg cramps) from December 2001 to October 2007 among adults aged 50 years and older, which were obtained from linked health care databases that contain the prescribing information for the 4.2 million residents of British Columbia, Canada; and (b) the Internet search volume from February 2004 to March 2012 for the term "leg cramps" (reflecting public interest), which we obtained from Google Trends data and geographically limited to the United States and Australia. We assessed seasonality by determining how well a least-squares sinusoidal model predicted variability in the outcomes.
resultsNew quinine prescriptions and Internet searches related to leg cramps were both seasonal, with highs in mid-summer and lows in mid-winter, and a peak-to-peak variability that was about two-thirds of the mean. Seasonality accounted for 88% of the observed monthly variability in new quinine prescriptions (p < 0.001) and 70% of the observed variability in Internet searches related to leg cramps (p < 0.001).
interpretationNew quinine prescriptions and Internet searches related to leg cramps were seasonal and roughly doubled between the winter lows and summer highs. Why a disorder of peripheral motor neurons displays such strong seasonality warrants exploration.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.