The relationship between obesity, low back pain, and lumbar disc degeneration when genetics and the environment are considered: a systematic review of twin studies

BACKGROUND CONTEXT: The relationships between obesity and low back pain (LBP) and lumbar disc degeneration (LDD) remain unclear. It is possible that familial factors, including genetics and early environment, affect these relationships.PURPOSE: To investigate the relationship between obesity-related measures (eg, weight, body mass index [BMI]) and LBP and LDD using twin studies, where the effect of genetics and early environment can be controlled.STUDY DESIGN: A systematic review with meta-analysis.METHODS: MEDLINE, CINAHL, Scopus, Web of Science, and EMBASE databases were searched from the earliest records to August 2014. All cross-sectional and longitudinal observational twin studies identified by the search strategy were considered for inclusion. Two investigators independently assessed the eligibility, conducted the quality assessment, and extracted the data. Metaanalyses (fixed or random effects, as appropriate) were used to pool studies'estimates of association.RESULTS: In total, 11 articles met the inclusion criteria. Five studies were included in the LBP analysis and seven in the LDD analysis. For the LBP analysis, pooling of the five studies showed that the risk of having LBP for individuals with the highest levels of BMI or weight was almost twice that of people with a lower BMI (odds ratio [OR] 1.8; 95% confidence interval [CI] 1.6-2.0; I-2 = 0%). A dose-response relationship was also identified. When genetics and the effects of a shared early environment were adjusted for using a within-pair twin case-control analysis, pooling of three studies showed a reduced but statistically positive association between obesity and prevalence of LBP (OR 1.5; 95% CI 1.1-2.1; I-2 = 0%). However, the association was further diminished and not significant (OR 1.4; 95% CI 0.8-2.3; I-2 = 0%) when pooling included two studies on monozygotic twin pairs only. Seven studies met the inclusion criteria for LDD. When familial factors were not controlled for, body weight was positively associated with LDD in all five cross-sectional studies. Only two cross-sectional studies investigated the relationship between obesity-related measures and LDD accounting for familial factors, and the results were conflicting. One longitudinal study in LBP and three longitudinal studies in LDD found no increase in risk in obese individuals, whether or not familial factors were controlled for.CONCLUSIONS: Findings from this review suggest that genetics and early environment are possible mechanisms underlying the relationship between obesity and LBP; however, a direct causal link between these conditions appears to be weak. Further longitudinal studies using the twin design are needed to better understand the complex mechanisms underlying the associations between obesity, LBP, and LDD.

Dietary patterns are associated with general and central obesity in elderly living in a Brazilian city

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Obesity does not lead to imbalance between myocardial phospholamban phosphorylation and dephosphorylation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cardiac dysfunction induced by obesity es not related to beta-adrenergic system impairment at the receptor-signalling pathway

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Macronutrient intake is correlated with dyslipidemia and low-grade inflammation in childhood obesity but mostly in male obese

Condition of hypoxia caused by hypertrophy of adipose cells in obesity triggers macrophages recruitment and production of cytokines. Additionally, high consumption of saturated fatty acids (SFA) and high glycemic index meals may contribute to oxidative stress and chronic low-grade inflammation by increases NF-kB activation. Thus, the aim of the study was to analyze the contribution of the macronutrients intake in the metabolic and inflammatory profile, by levels of lipoproteins, insulin resistance, anti and pro inflammatory cytokines, in obese adolescents according the gender. sample was composed by 37 adolescents, both genders, identified as obese by body mass index (BMI). Body composition was assessed by Dual-energy X-ray absorptiometry (DEXA) and measures of intra-abdominal adiposity (IAAT) and subcutaneous adiposity tissue (SAT) were done by ultrasound. Biochemical analyses were done and the measurement of cytokines; fatty acids and insulin were performed by the technique of immunoassay ELISA. The estimation of macronutrients consumption was made by 3 day food register regarding food intake. Statistical significance was set at p-value < 5% and the statistical software SPSS version 17.0 (SPSS Inc, Chicago, IL) performed all analyses. BMI (p = 0.316), FM (p = 0.416), IAAT (p = 0.505) and SAT (p = 0.935) presented similarities between genders. Cytokines and metabolic variables values were similar between the groups. Only in the male group, metabolic variables and cytokines were significant correlated with the consumption of total lipids or its fractions. Was observed that insulin concentration had significant interaction with MUFA(g) (= -18.4; p = 0.004) and adiponectin with CHO(g) (= -58.2; p = 0.032) in the group male and female, respectively. macronutrients intake is associated with low-grade inflammation in obesity, by production of inflammatory cytokines and alteration of the lipid profile, especially male obese adolescents which seem to be more responsive of this consumption when compared with female obese adolescents.

Impact of obesity on autonomic modulation, heart rate and blood pressure in obese young people

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Obesity induced by a sucrose-rich diet promotes deficits in bone mineralization and microarchitecture

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The role of oxidative stress in renal injury related to obesity

The mechanisms linking obesity to kidney damage are unknown. AGEs are responsible for renal damage in obese individuals. The receptor AGEs (RAGE) contributes to nuclear transcription factors that result in the production of proinflammatory cytokines and this seems to contribute to the development of renal disease. Thus, intervention with antioxidant can have an important effect in the prevention and treatment of pro-oxidant and pro-inflammatory state in the kidneys resulting from obesity.

Diversity of eating patterns and obesity in older adults: a new challenge

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A possible increase of activity of endothelial l-arginine/nitric oxide pathway in aortas of diet-induced obesity rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)