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Restless Legs Syndrome Linked to Hypertension in Women
by Steve Stiles, Medscape
October 13, 2011
Hypertension was significantly more prevalent among women who reported frequent symptoms of restless-legs syndrome (RLS)--that is, symptoms at least 15 times per month--compared with those who said they had them less often or not at all, according to a cross-sectional cut of data from the Women's Health Study 2 (WHS 2) [1].
The observed association between RLS and hypertension, which was independent of recognized hypertension risk factors, applied to both systolic and diastolic pressures and became stronger with increasing RLS severity, report the authors, led by Dr Salma Batool-Anwar (Brigham and Women's Hospital, Boston, MA).
The group's findings "are consistent with the previous literature suggesting a possible role for RLS in the pathogenesis of hypertension," they state in their report, published online October 10, 2011 in Hypertension. They caution against generalizing their results to men, although some of the prior research suggests the two conditions may be linked in both men and women.
In particular, the group points to research suggesting that 80% of people with RLS (characterized by "intense, unpleasant leg sensations and an irresistible urge to move the legs") also show periodic limb movements of sleep (PLMS). And PLMS, they note, is associated with periodic fluctuations in blood pressure.
"What appears to be a common theme between RLS and PLMS [regular limb movements during sleep] is that such leg movements are associated with sympathetically mediated elevations in both heart rate and blood pressure," write Drs Domenic Sica and David Leszczyszyn (Virginia Commonwealth University, Richmond, VA) in an accompanying editorial [2].
"A not-unreasonable hypothesis derived from these events is that the repeated overnight changes in blood pressure developing during nighttime RLS and PLMS episodes increase daytime blood pressure based on the cumulative effects of increased nocturnal sympathetic activity," they write.
Still, whether RLS is one cause of hypertension can't be determined from a cross-sectional study, Batool-Anwar noted for heartwire. It could be that RLS and hypertension simply share a common pathophysiology. But their analysis excluded women with conditions that might mimic RLS, including diabetics (who could have peripheral neuropathy), and RLS severity went up with hypertension prevalence, so the findings "point in the direction" of causation, she said.
The analysis included 65 544 women from the WHS 2 cohort who were given a probable diagnosis of RLS based on questionnaire responses; the diagnosis required that RLS symptoms occur at least five times per month. Excluded were any who were diabetic, currently had arthritis, or were pregnant.
Overall, the age-adjusted odds ratio (OR) for hypertension was 1.43 (95% CI 1.33?1.53, p<0.0001) among the women with RLS symptoms compared with those without symptoms; the significant relationship "did not materially change" (OR 1.20; 95% CI 1.10?1.30) after further adjustments for conditions with possible ties to RLS. There was a positive relationship between degree of RLS symptoms and hypertension prevalence.
Blood-Pressure Findings and Odds Ratio for Hypertension Among Women With Restless-Legs Syndrome by Symptom Frequency, Compared With No RLS Symptoms
All trends with increasing RLS symptoms, p<0.0001
*Adjusted for age, race, body-mass index, physical activity, menopausal status, smoking status, use of analgesics and oral contraceptives, and intake of alcohol, caffeine, folate, and iron
Should further research show that treating RLS could also treat hypertension, "it could be as simple as replacing iron, because most of the time [RLS] is related to iron deficiency," Batool-Anwar said. "Also a healthy lifestyle: [controlling] intake of caffeine and alcohol and [reducing] weight." And if that doesn't help, drug therapy is available.
But Sica and Leszczyszyn also emphasize that the findings "are observational and cannot in any way be viewed as being mechanistic; thus, no insight can be provided into whether treatment of RLS could in any sort of meaningful way lower blood pressure."
Besides, they note, "the magnitude of blood-pressure change in millimeters of mercury was very small, even in those with the highest frequency of RLS, such that even the best clinician would not have identified a blood-pressure change attributed to RLS."
[h=4]References[/h]
by Steve Stiles, Medscape
October 13, 2011
Hypertension was significantly more prevalent among women who reported frequent symptoms of restless-legs syndrome (RLS)--that is, symptoms at least 15 times per month--compared with those who said they had them less often or not at all, according to a cross-sectional cut of data from the Women's Health Study 2 (WHS 2) [1].
The observed association between RLS and hypertension, which was independent of recognized hypertension risk factors, applied to both systolic and diastolic pressures and became stronger with increasing RLS severity, report the authors, led by Dr Salma Batool-Anwar (Brigham and Women's Hospital, Boston, MA).
The group's findings "are consistent with the previous literature suggesting a possible role for RLS in the pathogenesis of hypertension," they state in their report, published online October 10, 2011 in Hypertension. They caution against generalizing their results to men, although some of the prior research suggests the two conditions may be linked in both men and women.
In particular, the group points to research suggesting that 80% of people with RLS (characterized by "intense, unpleasant leg sensations and an irresistible urge to move the legs") also show periodic limb movements of sleep (PLMS). And PLMS, they note, is associated with periodic fluctuations in blood pressure.
"What appears to be a common theme between RLS and PLMS [regular limb movements during sleep] is that such leg movements are associated with sympathetically mediated elevations in both heart rate and blood pressure," write Drs Domenic Sica and David Leszczyszyn (Virginia Commonwealth University, Richmond, VA) in an accompanying editorial [2].
"A not-unreasonable hypothesis derived from these events is that the repeated overnight changes in blood pressure developing during nighttime RLS and PLMS episodes increase daytime blood pressure based on the cumulative effects of increased nocturnal sympathetic activity," they write.
Still, whether RLS is one cause of hypertension can't be determined from a cross-sectional study, Batool-Anwar noted for heartwire. It could be that RLS and hypertension simply share a common pathophysiology. But their analysis excluded women with conditions that might mimic RLS, including diabetics (who could have peripheral neuropathy), and RLS severity went up with hypertension prevalence, so the findings "point in the direction" of causation, she said.
The analysis included 65 544 women from the WHS 2 cohort who were given a probable diagnosis of RLS based on questionnaire responses; the diagnosis required that RLS symptoms occur at least five times per month. Excluded were any who were diabetic, currently had arthritis, or were pregnant.
Overall, the age-adjusted odds ratio (OR) for hypertension was 1.43 (95% CI 1.33?1.53, p<0.0001) among the women with RLS symptoms compared with those without symptoms; the significant relationship "did not materially change" (OR 1.20; 95% CI 1.10?1.30) after further adjustments for conditions with possible ties to RLS. There was a positive relationship between degree of RLS symptoms and hypertension prevalence.
Blood-Pressure Findings and Odds Ratio for Hypertension Among Women With Restless-Legs Syndrome by Symptom Frequency, Compared With No RLS Symptoms
| Parameter | No RLS, n=61 321 | RLS 5-14 times/mo, n=2475 | RLS >15 times/mo, n=1748 |
| Mean SBP (mm Hg) | 130 | 131 | 133 |
| Mean DBP (mm Hg) | 80 | 81 | 82 |
| Hypertension prevalence (%) | 21.4 | 26.0 | 33.0 |
| Age-adjusted OR (95% CI) | 1 | 1.24 (1.13?1.36) | 1.73 (1.56?1.92) |
| OR with further adjustments* | 1 | 1.06 (0.94?1.18) | 1.41 (1.24?1.61) |
All trends with increasing RLS symptoms, p<0.0001
*Adjusted for age, race, body-mass index, physical activity, menopausal status, smoking status, use of analgesics and oral contraceptives, and intake of alcohol, caffeine, folate, and iron
Should further research show that treating RLS could also treat hypertension, "it could be as simple as replacing iron, because most of the time [RLS] is related to iron deficiency," Batool-Anwar said. "Also a healthy lifestyle: [controlling] intake of caffeine and alcohol and [reducing] weight." And if that doesn't help, drug therapy is available.
But Sica and Leszczyszyn also emphasize that the findings "are observational and cannot in any way be viewed as being mechanistic; thus, no insight can be provided into whether treatment of RLS could in any sort of meaningful way lower blood pressure."
Besides, they note, "the magnitude of blood-pressure change in millimeters of mercury was very small, even in those with the highest frequency of RLS, such that even the best clinician would not have identified a blood-pressure change attributed to RLS."
[h=4]References[/h]
- Batool-Anwar S, Malhotra A, Forman J, et al. Restless legs syndrome and hypertension in middle-aged women. Hypertension 2011; DOI:10.1161/HYPERTENSIONAHA.111.174037. Available at: http://hyper.ahajournals.org. Abstract
- Sica D, Leszczyszyn D. Sleep: Yet to be mapped waters for blood pressure. Hypertension 2011; DOI:10.1161/HYPERTENSIONAHA.111.180125. Available at: http://hyper.ahajournals.org. Abstract
