MedicalResearch.com Interview with:
Scott R. Garrison MD PhD
Associate Professor, Department of Family Medicine
Director, Pragmatic Trials Collaborative
Faculty of Medicine University of Alberta Edmonton
MedicalResearch: What is the background for this study? What are the main findings?
Dr. Garrison: Nocturnal leg cramps (also called rest cramps) are painful muscle tightenings, most often in the legs or feet, that are brought on by rest and often wake the sufferer from sleep. They are very common in older adults and can also occur during pregnancy. Having read anecdotal mention that the rest cramps of pregnancy appeared to be worse in summer we sought cohort level evidence to determine whether the more common presentation of age-related rest cramps was also seasonal. To do this we primarily looked at new quinine starts in the province of British Columbia over a period of several years. British Columbia has a publicly funded health care system and maintains electronic records on all health services, including prescription drugs, provided to its roughly 4.2 million residents. Quinine is approved for the treatment of acute malaria in Canada but is instead almost exclusively used off-label to prevent rest cramps. As such, new quinine starts are an excellent marker for new or escalating cramp burden. We also looked at Internet searches, geographically limited to the USA, for the term “leg cramps” (reflecting public interest) obtained from the Google Trends Search Volume Index Tool. Seasonality for both of these indicators of cramp burden was assessed by determining how well a least squares minimizing sinusoidal model predicted variability.
We found that quinine starts and "leg cramp" related Internet queries were both strikingly sinusoidal with a 365-day periodicity (mid-summer high, mid-winter low) and a peak-to-peak variability that is approximately 2/3 of the mean. Seasonality accounted for 88% of the observed monthly variability (p < 0.0001) in quinine starts, and 70% of the observed variability (p < 0.0001) in “leg cramp” related internet searches. (more…)MedicalResearch.com Interview with:
Scott R. Garrison MD PhD
Associate Professor, Department of Family Medicine
Director, Pragmatic Trials Collaborative
Faculty of Medicine University of Alberta Edmonton
MedicalResearch: What is the background for this study? What are the main findings?
Dr. Garrison: Nocturnal leg cramps (also called rest cramps) are painful muscle tightenings, most often in the legs or feet, that are brought on by rest and often wake the sufferer from sleep. They are very common in older adults and can also occur during pregnancy. Having read anecdotal mention that the rest cramps of pregnancy appeared to be worse in summer we sought cohort level evidence to determine whether the more common presentation of age-related rest cramps was also seasonal. To do this we primarily looked at new quinine starts in the province of British Columbia over a period of several years. British Columbia has a publicly funded health care system and maintains electronic records on all health services, including prescription drugs, provided to its roughly 4.2 million residents. Quinine is approved for the treatment of acute malaria in Canada but is instead almost exclusively used off-label to prevent rest cramps. As such, new quinine starts are an excellent marker for new or escalating cramp burden. We also looked at Internet searches, geographically limited to the USA, for the term “leg cramps” (reflecting public interest) obtained from the Google Trends Search Volume Index Tool. Seasonality for both of these indicators of cramp burden was assessed by determining how well a least squares minimizing sinusoidal model predicted variability.
We found that quinine starts and "leg cramp" related Internet queries were both strikingly sinusoidal with a 365-day periodicity (mid-summer high, mid-winter low) and a peak-to-peak variability that is approximately 2/3 of the mean. Seasonality accounted for 88% of the observed monthly variability (p < 0.0001) in quinine starts, and 70% of the observed variability (p < 0.0001) in “leg cramp” related internet searches. (more…)