Parental chronic widespread pain and the association with chronic widespread pain in adult offspring: Family-linkage data from the Norwegian HUNT Study.

BACKGROUND: Individuals experiencing chronic widespread pain (CWP) have greater disability and poorer quality of life compared to those with other chronic painful conditions; although research identifying risk factors for CWP is lacking. We aimed to investigate whether parental CWP increases the risk of offspring CWP, and if offspring body mass index (BMI) and leisure time physical activity modify this association. METHODS: We included 6589 parent-offspring trios participating in the Norwegian HUNT Study in 1995-1997 and 2006-2008. Logistic regression was used to calculate adjusted odd ratios (ORs) (95% confidence intervals, CIs) as estimates of relative risk for offspring CWP. We analysed the joint effect of parental CWP and offspring BMI or leisure time physical activity on offspring risk of CWP and calculated the relative excess risk due to interaction (RERI). RESULTS: In total, 886 (13.5%) offspring developed CWP during follow-up. Having one (OR = 1.23, 95% CI, 1.05-1.44) or both parents with CWP (OR = 1.89, 95% CI, 1.50-2.38) increased the risk of offspring CWP. In analyses of joint effects, ORs were 1.84 (95% CI, 1.31-2.56) and 3.35 (95% CI, 1.94-5.77) in normal weight and obese offspring, respectively, when both parents had CWP. The estimate of RERI suggested some synergistic effect (RERI = 1.19, 95% CI, -0.68 to 3.05), although precision was low. Risk of CWP was similar in active (OR = 2.05, 95% CI, 1.56-2.70) and inactive (OR = 1.96, 95% CI, 1.31-2.91) offspring when both parents had CWP. CONCLUSION: Parental CWP increases the risk of CWP in adult offspring, particularly if both parents have CWP and offspring are obese. This highlights a familial predisposition for CWP and an important target group for preventive measures. SIGNIFICANCE: The parent-offspring transmission of CWP is stronger in obese offspring (particularly when both parents have CWP). This study is the first to investigate the interaction between modifiable lifestyle factors, familial factors and CWP.

Neighborhood walkability moderates the association between low back pain and physical activity: A co-twin control study.

The aim of this study was to investigate whether neighborhood walkability moderates the association between low back pain (LBP) and physical activity (PA), using a co-twin design to control for genetics and shared environmental factors. A cross-sectional analysis was performed on 10,228 twins from the Washington State Twin Registry with available data on LBP from recruitment surveys between 2009 and 2013. LBP within the past 3months was our exposure variable. Our outcome variables were sufficient moderate or vigorous-intensity PA (MVPA, defined as at least 75min of vigorous-intensity PA, or 150min of moderate-intensity PA per week), and walking (≥150min per week). Neighborhood walkability, estimated using the commercially available Walk Score®, was our moderator variable. After controlling for the influence of genetics and shared environment, individuals reporting LBP were significantly less likely to engage in sufficient MVPA if they lived in a neighborhood with high walkability (OR=0.59, 95%CI: 0.36-0.96). There was no association between LBP and sufficient MVPA for individuals living in a neighborhood with low walkability (OR=1.27, 95%CI: 0.93-1.72), demonstrating that walkability is a significant moderator of the association between LBP and PA (interaction p=0.013). These findings were similar for the association between LBP and walking (high walkability OR=0.42, 95%CI: 0.22-0.78; low walkability OR=0.71, 95%CI: 0.46-1.12), although the interaction was not significant (p=0.700). Neighborhood walkability moderates the association between LBP and PA. Our results highlight the importance of targeting interventions promoting PA towards individuals with LBP living in a neighborhood with good walkable access to amenities.

The Beneficial Effects of Physical Activity: Is It Down to Your Genes? A Systematic Review and Meta-Analysis of Twin and Family Studies.

BACKGROUND: There is evidence for considerable heterogeneity in the responsiveness to regular physical activity (PA) which might reflect the influence of genetic factors. The aim of this systematic review was to assess whether the response to a PA intervention for measures of body composition and cardiorespiratory fitness is (i) correlated within twin pairs and/or families and (ii) more correlated in monozygotic twins (MZ) compared to dizygotic twins (DZ), which would be consistent with genetic effects. METHODS: We performed electronic database searches, combining key words relating to "physical activity" and "genetics", in MEDLINE, CINAHL, EMBASE, SPORTS Discuss, AMED, PsycINFO, WEB OF SCIENCE, and SCOPUS from the earliest records to March 2016. Twin and family studies were included if they assessed body composition and/or cardiorespiratory fitness following a PA intervention, and provided a heritability estimate, maximal heritability estimate, or within MZ twin pair correlation (rMZ). Data on heritability (twin studies), maximal heritability (family studies), and the rMZ were extracted from included studies, although heritability estimates were not reported as small sample sizes made them uninformative. RESULTS: After screening 224 full texts, nine twin and five family studies were included in this review. The pooled rMZ in response to PA was significant for body mass index (rMZ = 0.69, n = 58), fat mass (rMZ = 0.58, n = 48), body fat percentage (rMZ = 0.55, n = 72), waist circumference (rMZ = 0.50, n = 27), and VO2max (rMZ = 0.39, n = 48), where "n" represents the total number of twin pairs from all studies. Maximal heritability estimates ranged from 0-21% for measures of body composition, and 22-57% for cardiorespiratory fitness. Twin studies differed in sample age, baseline values, and PA intervention, although the exclusion of any one study did not affect the results. CONCLUSIONS: Shared familial factors, including genetics, are likely to be a significant contributor to the response of body composition and cardiorespiratory fitness following PA. Genetic factors may explain individual variation in the response to PA. TRIAL REGISTRATIONS: PROSPERO Registration No CRD42015020056 .