Walking, cycling to work protect against hospitalization for sciatica
Walking or cycling to work is protective against hospitalization for sciatica, whereas smoking and obesity increase the risk, according to a recent study.
“Walking and cycling can be recommended for the prevention of sciatica in the general population,” researchers said. “The public health implications of commuting to work by walking or cycling can be substantial.”
A random-effects individual participant data meta-analysis was conducted including four Finnish prospective cohort studies (Health 2000 Survey, Mobile Clinic Survey, Helsinki Health Study and Young Finns Study) that consisted of 34,589 participants and 1,259 hospitalizations for sciatica during 12 to 30 years of follow-up. Sciatica was based on hospital discharge register data.
Current smokers at baseline showed a 33-percent (95 percent CI, 13 to 56 percent) heightened risk of subsequent hospitalization for sciatica, while past smokers were no longer at increased risk, after adjustment for confounding factors. Obesity defined by body mass index and abdominal obesity defined by waist circumference also increased the hospitalization risk for sciatica by 36 (7 to 74 percent) and 41 percent (3 to 93 percent), respectively. [Am J Med 2017;130:1408–1414.e6]
On the other hand, walking or cycling to work was protective against hospitalization for sciatica, reducing the risk by 33 percent (4 to 53 percent). This effect was independent of body weight and other leisure activities. However, other types of leisure activities had no statistically significant effect.
“The findings of the current study are in line with our earlier meta-analyses. The effect sizes are also similar to those of the meta-analyses. However, the previous studies were mostly cross-sectional or case control studies, and only a limited number of cohort studies focused on clinically verified sciatica,” researchers said. [Am J Epidemiol 2014;179:929–937; Am J Med 2016;129:64–73; Eur J Pain 2016;20:1563–1572]
Furthermore, earlier meta-analyses showed that moderate or high level of leisure-time physical activity was protective against lumbar radicular and chronic low back pain by 11 to 16 percent only. This finding supports the current result that the protective effects of physical activity on most lower back outcomes are minor. [Eur J Pain 2016;20:1563–1572; Br J Sports Med 2017;doi:10.1136/bjsports-2016-097352]
There are several underlying mechanisms through which lifestyle risk factors contribute to sciatica.
“Smoking reduces perfusion around the intervertebral discs, increases production and release of inflammatory cytokines in intervertebral discs, slows down the healing process, and causes intervertebral disc degeneration,” according to researchers [Spine 1997;22:1642–1647; Semin Arthritis Rheum 2007;37:174–181; J Orthop Sci 2006;11:191–197; J Orthop Sci 2004;9:135–141; BMC Musculoskelet Disord 2012;13:183; Osteoarthritis Cartilage 2012;20:896–905; Spine 2004;29:568–575]
Obesity increases secretion of leptin and inflammatory mediators from excess adipose tissue and interferes with the nutrition or healing of the intervertebral discs. [Circ Res 2005;96:939–949; J Bone Joint Surg Am 2013;95:1–8]
“Walking and cycling to work prevent sciatica because they are regular low-level physical activities that do not strain the lower back, while a moderate level of other leisure-time physical activities may include sports that strain the lower back, particularly in individuals who occasionally practice them,” researchers said. [Sports Health 2009;1:212–222]