The relationship between birthweight and early age-related maculopathy: the atherosclerosis risk in communities study

Features of Retinal Neurogenesis as a Key Factor of Age-Related Neurodegeneration: Myth or Reality?

Age-related macular degeneration (AMD) is a complex multifactorial neurodegenerative disease that constitutes the most common cause of irreversible blindness in the elderly in the developed countries. Incomplete knowledge about its pathogenesis prevents the search for effective methods of prevention and treatment of AMD, primarily of its "dry" type which is by far the most common (90% of all AMD cases). In the recent years, AMD has become "younger": late stages of the disease are now detected in relatively young people. It is known that AMD pathogenesis-according to the age-related structural and functional changes in the retina-is linked with inflammation, hypoxia, oxidative stress, mitochondrial dysfunction, and an impairment of neurotrophic support, but the mechanisms that trigger the conversion of normal age-related changes to the pathological process as well as the reason for early AMD development remain unclear. In the adult mammalian retina, de novo neurogenesis is very limited. Therefore, the structural and functional features that arise during its maturation and formation can exert long-term effects on further ontogenesis of this tissue. The aim of this review was to discuss possible contributions of the changes/disturbances in retinal neurogenesis to the early development of AMD.

Body size at birth and age-related macular degeneration in old age

PURPOSE

To study associations between body size at birth and age-related macular degeneration (AMD) in old age.

METHODS

The study sample consists of 1497 community-dwelling individuals (56.1% women) aged 67-89 years with birth data and retinal data collected twice in old age 5 years apart. Birth data (weight, length, birth order) were extracted from original birth records. Digital retinal photographs were graded to determine AMD status. Data on covariates were collected at the baseline physical examination in old age. Multivariable regression analyses were used to study the association between birth data and AMD adjusting for known confounding factors, including birth year cohort effects.

RESULTS

The prevalence and 5-year incidence of any AMD were 33.1% and 17.0%, respectively. Men and women born in 1930-1936 were significantly leaner and slightly longer at birth compared to those in earlier birth cohorts. There were no consistent associations between weight, length or ponderal index (PI) at birth and AMD in old age even when stratified by birth cohort. Age-related macular degeneration (AMD) prevalence (39.8%) and 5-year incidence (28.6%) were highest in individuals who were in the highest quartile of PI at birth and who were obese in old age.

CONCLUSION

Body size at birth was not consistently associated with AMD in old age, suggesting that intrauterine growth might have little direct importance in the development of AMD in old age. It is possible that some yet unknown factors related to larger size at birth and obesity in old age may explain differences in the prevalence and incidence of AMD in the ageing population.

Low Birth Weight Is Linked to Age-Related Macular Degeneration: Results From the Population-Based Gutenberg Health Study (GHS)

Purpose

This study analyzed whether low birth weight is linked to prevalence and incidence of age-related maculopathy (AMD) in adulthood.

Methods

The Gutenberg Health Study (GHS) is a population-based, observational cohort study in Germany. GHS participants at an age from 35 to 74 years were included. An ophthalmologic examination with fundus photography was carried out. Fundus photographs were graded according to the Rotterdam Grading Scheme for AMD at baseline and at the 5-year follow-up examination. Participants were divided into three different birth weight groups (low: <2500 g; normal: 2500-4000 g; and high: >4000 g). Poisson regression analysis with adjustment for several confounders was used to assess associations between birth weight and AMD prevalence (overall, early, late AMD) and 5-year cumulative incidence.

Results

Overall, 6492 participants were included (3538 female, aged 50.7 ± 10.4 years). Prevalence of total AMD was highest in the low birth weight group (11.2%; 40/358) compared to the normal birth weight group (6.5%; 346/5328) and the high birth weight group (8.4%; 68/806). Low birth weight was associated with overall AMD prevalence (prevalence ratio [PR] = 1.54, P = 0.006), and in particular with early AMD prevalence (PR = 1.52; P = 0.01). No association was observed between low birth weight and cumulative 5-year incidence of AMD.

Conclusions

Our analyses indicate that low birth weight may lead to higher prevalence of retinal diseases in later life, as we observed for AMD. Our results are limited due to missing data and loss to follow-up, but may be a first hint that AMD has one of its origins in early life.

The associations of high birth weight with blood pressure and hypertension in later life: a systematic review and meta-analysis

The 'fetal origin hypothesis' suggests that metabolic diseases are directly related to poor nutritional status in early life. Thus, a high birth weight (HBW) may pose a lower risk than normal birth weight. Overweight and overnutrition are among the most widely recognized risk factors of metabolic diseases. To explore the possible effects of HBW on blood pressure and hypertension, a systematic review was performed. The PubMed and Embase databases were searched for relevant studies. The outcomes included systolic blood pressure (SBP), diastolic blood pressure (DBP) and hypertension. We included all of the studies that assessed the differences in outcomes for children aged >1 year between those born with normal birth weight (birth weight between 2500 and 4000 g or between the 10th and 90th percentiles for their gestational age) and those born with HBW (birth weight4000 g or 90th percentile for their gestational age). The outcomes were analyzed descriptively and by conducting a meta-analysis. Thirty-one studies satisfied the inclusion criteria. The mean difference in blood pressure and the relative risk of hypertension between individuals with HBW and individuals with normal birth weight was inversely associated with age. SBP and DBP, as well as the prevalence of hypertension, were higher in younger children with HBW but lower in older adults with HBW compared with individuals with normal birth weight. The findings suggested that an individual with HBW is prone to hypertension and higher blood pressure during childhood. However, a 'catch-down' effect in the elevation of blood pressure is observed in subjects with HBW as they grow older. Thus, older individuals with HBW are less susceptible to hypertension than those with normal birth weight.

Birth weight and subsequent blood pressure: a meta-analysis

Hypertension is becoming an important health problem in many countries. The 'small baby syndrome hypothesis' suggests that an inverse linear relationship exists between birth weight and later risk of hypertension; however, this relationship is under debate. We conducted a meta-analysis to examine the association between birth weight and subsequent blood pressure. Among 78 studies reporting on the association between birth weight and subsequent blood pressure, 20 articles (reporting 27 original studies) were eligible for inclusion. Low birth weight (< 2500 g) compared with birth weight greater than 2500 g was associated with an increased risk of hypertension (odds ratio [OR] 1.21; 95% confidence interval [CI] 1.13, 1.30); high birth weight (> 4000 g) compared with birth weight less than 4000 g was associated with a decreased risk of hypertension (OR 0.78; 95% CI 0.71, 0.86). When low birth weight (< 2500 g) was compared with birth weight greater than 2500 g, mean systolic blood pressure (SBP) increased by 2.28 mmHg (95% CI 1.24, 3.33); when high birth weight (> 4000 g) was compared with birth weight less than 4000 g, mean SBP decreased by 2.08 mmHg (95% CI -2.98, -1.17). These findings indicate that there is an inverse linear association between birth weight and later risk of hypertension, and that this association primarily exists between birth weight and SBP.