Osteoporosis is a major health problem, especially in elderly populations, and is associated with fragility fractures at the hip, spine, and wrist. Hip fracture contributes to both morbidity and mortality in the elderly. The demographics of world populations are set to change, with more elderly living in developing countries, and it has been estimated that by 2050 half of hip fractures will occur in Asia. This review conducted using the PubMed database describes the incidence of hip fracture in different regions of the world and discusses the possible causes of this wide geographic variation. The analysis of data from different studies show a wide geographic variation across the world, with higher hip fracture incidence reported from industrialized countries as compared to developing countries. The highest hip fracture rates are seen in North Europe and the US and lowest in Latin America and Africa. Asian countries such as Kuwait, Iran, China, and Hong Kong show intermediate hip fracture rates. There is also a north–south gradient seen in European studies, and more fractures are seen in the north of the US than in the south. The factors responsible of this variation are population demographics (with more elderly living in countries with higher incidence rates) and the influence of ethnicity, latitude, and environmental factors. The understanding of this changing geographic variation will help policy makers to develop strategies to reduce the burden of hip fractures in developing countries such as India, which will face the brunt of this problem over the coming decades.

Common variants at only two loci, FTO and MC4R, have been reproducibly associated with body mass index (BMI) in humans. To identify additional loci, we conducted meta-analysis of 15 genome-wide association studies for BMI (n > 32,000) and followed up top signals in 14 additional cohorts (n > 59,000). We strongly confirm FTO and MC4R and identify six additional loci (P < 5 × 10−8): TMEM18, KCTD15, GNPDA2, SH2B1, MTCH2 and NEGR1 (where a 45-kb deletion polymorphism is a candidate causal variant). Several of the likely causal genes are highly expressed or known to act in the central nervous system (CNS), emphasizing, as in rare monogenic forms of obesity, the role of the CNS in predisposition to obesity.

Background

A number of studies have shown strong graded positive relationships between size at birth and grip strength and estimates of muscle mass in older people. However no studies to date have included direct measures of muscle size.

Methods

We studied 313 men and 318 women born in Hertfordshire UK between 1931 and 1939 who were still resident there and had historical records of growth in early life. Information on lifestyle was collected and participants underwent peripheral quantitative computed tomography to directly measure forearm and calf muscle size.

Results

Birth weight was positively related to forearm muscle area in the men (r = 0.24 p < 0.0001) and women (r = 0.17 p =0.003). There were similar but weaker associations between birth weight and calf muscle area in the men (r=0.13, p=0.03) and in the women (r=0.17, p=0.004). These relationships were all attenuated by adjustment for adult size.

Conclusion

We present first evidence that directly measured muscle size in older men and women is associated with size at birth. This may reflect tracking of muscle size and is important because it suggests that benefit may be gained from taking a life course approach both to understanding the aetiology of sarcopenia and to developing effective interventions.

OBJECTIVES

To examine relationships between diet and grip strength in older men and women, and to determine whether these relationships are modified by prenatal growth.

DESIGN

Cross-sectional and retrospective cohort study

SETTING

Hertfordshire, UK

PARTICIPANTS

Two thousand, nine hundred and eighty three men and women aged 59 to 73 years who were born and still live in Hertfordshire, UK

MEASUREMENTS

Weight at birth recorded in Health Visitor ledgers. Current food and nutrient intake assessed using an administered food frequency questionnaire, grip strength was measured with a hand-held dynamometer.

RESULTS

Grip strength was positively associated with height and weight at birth, and inversely related to age (all P<0.001). Of the dietary factors considered in relation to grip strength, the most important was fatty fish consumption. An increase in grip strength of 0.43kg (95% CI 0.13 to 0.74) in men (P=0.005), and 0.48kg (95% CI 0.24 to 0.72) in women (P<0.001), was observed for each additional portion of fatty fish consumed per week. These relationships were independent of adult height, age and birth weight, each of which had additive effects on grip strength. There was no evidence of interactive effects of weight at birth and adult diet on grip strength.

CONCLUSION

These data suggest that fatty fish consumption can have an important influence on muscle function in older men and women. This raises the possibility that the anti-inflammatory actions of n-3 fatty acids may play a role in the prevention of sarcopenia.

Background

Body mass index (BMI) and bone mineral density (BMD) are positively correlated in several studies, but few data are available relating bone density, lipid profile and anthropometric measures. We addressed these relationships in a large well-characterised cohort of men and women (The Hertfordshire Cohort Study, UK).

Methods

Four hundred and sixty five men and 448 women from Hertfordshire, UK were recruited. Information was available on demographic and lifestyle factors, anthropometric measurements, body fat percentage, fasting triglycerides, cholesterol (total, HDL, LDL), apolipoprotein (a) and apolipoprotein (b); bone mineral density (BMD) was recorded at the lumbar spine and total femur.

Results

BMD at the lumbar spine (males r=0.15, p=0.001; females r=0.14 p=0.003) and total femoral region (males r=0.18, p=0.0001; females r==0.16, p=0.0008) was related to serum triglyceride level, even after adjustment for waist hip ratio, age, social class and lifestyle factors, but not if body fat percentage was substituted for waist-hip ratio in the regression model. Fasting HDL cholesterol level was related to lumbar spine BMD in women (r=−0.15, p=0.001) and total femoral BMD (males r=−0.15, p=0.002; females r=−0.23, p<0.0001); these relationships were also attenuated by adjustment for body fat percentage but not waist hip ratio. No relationships were seen between total or LDL cholesterol with BMD.

Conclusions

We have demonstrated relationships between lipid profile and BMD that are robust to adjustment for one measure of central obesity (waist-hip ratio) but not total body fat.

Infant growth is a determinant of adult bone mass, and poor childhood growth is a risk factor for adult hip fracture. Peripheral quantitative computed tomography (pQCT) allows non-invasive assessment of bone strength. We utilised this technology to examine relationships between growth in early life and bone strength.

We studied 313 men and 318 women born in Hertfordshire between 1931-39 who were still resident there in adult life, for whom detailed early life records were available. Lifestyle factors were evaluated by questionnaire, anthropometric measurements made, and peripheral QCT examination of the radius and tibia performed (Stratec 4500).

Birthweight and conditional weight at one year were strongly related to radial and tibial length in both sexes (p<0.001), and to measures of bone strength [fracture load X, fracture load Y, polar strength strain index (SSI)] at both the radius and tibia. These relationships were robust to adjustment for age, body mass index (BMI), social class, cigarette and alcohol consumption, physical activity, dietary calcium intake, HRT use and menopausal status in women. Among men, BMI was strongly positively associated with radial (r=0.46, p=0.001) and tibial (r=0.24, p=0.006) trabecular bone mineral density (BMD). Current smoking was associated with lower cortical (radius: p=0.0002; tibia: p=0.08) and trabecular BMD (radius: p=0.08; tibia: p=0.04) in males. Similar trends of BMD with these anthropometric and lifestyle variables were seen in women but they were non-significant. Current HRT use was associated with greater female cortical (radius: p=0.0002; tibia: p=0.001) and trabecular (radius: p=0.008; tibia: p=0.04) BMD. Current HRT use was also associated with greater radial strength (polar SSI: p=0.006; fracture load x: p=0.005; fracture load y: p=0.02) in women. Women who had sustained any fracture since the age of 45 years had lower radial total (p=0.0001), cortical (p<0.005) and trabecular (p=0.0002) BMD, poorer forearm bone strength [polar SSI (p=0.006), fracture load X & Y (p=0.02)], and lower tibial total (p<0.001), cortical (p=0.008) and trabecular (p=0.0001) BMD.

We have shown that growth in early life is associated with bone size and strength in a UK population aged 65-73 years. Lifestyle factors were associated with volumetric bone density in this population.

Recent studies have shown that people with poor early growth have an increased risk of sarcopenia. Sarcopenia is an important risk factor for falls but it is not known whether poor early growth is related to falls. We investigated this in the Hertfordshire Cohort Study where 2148 participants completed a falls history. Grip strength was used as a marker of sarcopenia. Birth weight, weight at one year and conditional infant growth were analysed in relation to falls history. The prevalence of any fall in the last year was 14.3% for men and 22.5% for women. Falls in the last year were inversely related to adult grip strength, height and walking speed in men and women as well as to lower conditional infant growth in men (OR 1.27 [95% CI 1.04, 1.56] per SD decrease in conditional infant growth, p=0.02). This association was attenuated after adjustment for grip strength. Our findings support an association between poor early growth and falls in older men which appears to be mediated partly through sarcopenia. The lack of relationship with birth weight suggests that postnatal rather than prenatal influences on muscle growth and development may be important for risk of falls in later life.

Objective

To assess if a coding variant in the gene encoding transient receptor potential cation channel, subfamily V, member 1 (TRPV1) is associated with genetic risk of painful knee osteoarthritis (OA).

Methods

The Ile585Val TRPV1 variant encoded by rs8065080 was genotyped in 3270 cases of symptomatic knee OA, 1098 cases of asymptomatic knee OA and 3852 controls from seven cohorts from the UK, the USA and Australia. The genetic association between the low-pain genotype Ile–Ile and risk of symptomatic and asymptomatic knee OA was assessed.

Results

The TRPV1 585 Ile–Ile genotype, reported to be associated with lower thermal pain sensitivity, was associated with a lower risk of symptomatic knee OA in a comparison of symptomatic cases with healthy controls, with an odds ratio (OR) of 0.75 (95% CI 0.64 to 0.88; p=0.00039 by meta-analysis) after adjustment for age, sex and body mass index. No difference was seen between asymptomatic OA cases and controls (OR=1.02, 95% CI 0.82 to 1.27 p=0.86) but the Ile–Ile genotype was associated with lower risk of symptomatic versus asymptomatic knee OA adjusting for covariates and radiographic severity (OR=0.73, 95% CI 0.57 to 0.94 p=0.0136). TRPV1 expression in articular cartilage was increased by inflammatory cytokines (tumour necrosis factor α and interleukin 1). However, there were no differences in TRPV1 expression in healthy and arthritic synovial tissue.

Conclusions

A genotype involved in lower peripheral pain sensitivity is significantly associated with a decreased risk of painful knee OA. This indicates a role for the pro-nociceptive gene TRPV1 in genetic susceptibility to symptomatic knee OA, which may also be influenced by a role for this molecule in cartilage function.