Publications by authors named "Michael P Gardner"

Aims: People with pre-diabetes are at high risk of progressing to type 2 diabetes. This progression is not well characterised by ethnicity, deprivation and age, which we describe in a large cohort of individuals with pre-diabetes.

Methods: A retrospective cohort study with The Health Improvement Network (THIN) database was conducted.

View Article and Find Full Text PDF

Objectives: We conducted an individual participant meta-analysis to test the hypothesis that cortisol patterns indicative of dysregulated hypothalamic-pituitary-adrenal axis functioning would be prospectively associated with poorer well-being at follow-up.

Setting: Four large UK-based cohort studies.

Participants: Those providing valid salivary or serum cortisol samples (n=7515 for morning cortisol; n=1612 for cortisol awakening response) at baseline (age 44-82) and well-being data on the Warwick Edinburgh Mental Wellbeing Scale at follow-up (0-8 years) were included.

View Article and Find Full Text PDF

Adult cognition and age-related cognitive decline can be influenced by dysregulation of the hypothalamic pituitary adrenal axis with concomitant changes in cortisol levels. However, very little is known about the role of childhood cognition and educational attainment in this relationship. Using data from the British 1946 birth cohort, the present study investigated: (1) associations between cortisol levels and patterns and cognitive function in midlife; (2) direct and interactive effects of childhood cognition, educational attainment and cortisol on cognitive function in midlife.

View Article and Find Full Text PDF

Purpose: There is inconclusive evidence on whether vitamin D therapy reduces cancer risk. We investigated the effect of vitamin D (±calcium) supplementation on the risk of breast, ovarian, uterine, colorectal, and lung cancer in women.

Methods: We conducted a case-control study using the UK Clinical Practice Research Datalink (CPRD); cases were women aged ≥55 years with a first diagnosis of either breast, colorectal, lung, ovarian, or uterine cancer between 2002 and 2009, with at least 5 years of CPRD follow-up prior to the date of diagnosis, and controls were women without cancer, frequency-matched to cases by year of birth, date of study entry, length of follow-up, and general practice.

View Article and Find Full Text PDF

Background: Telomeres are involved in cellular ageing and shorten with increasing age. If telomere length is a valuable biomarker of ageing, then telomere shortening should be associated with worse physical performance, an ageing trait, but evidence for such an association is lacking. The purpose of this study was to examine whether change in telomere length is associated with physical performance.

View Article and Find Full Text PDF

Background: Two previous reviews found that access-enhancing interventions were effective in increasing mammography uptake amongst low-income women. The purpose of this study was to estimate the magnitude of the effect of interventions used to increase uptake of mammography amongst low-income women.

Methods: Searches were conducted in MEDLINE and EMBASE (2002-April 2012) using relevant MeSH terms and keywords.

View Article and Find Full Text PDF

The association between functioning of the hypothalamic pituitary adrenal (HPA) axis and physical performance at older ages remains poorly understood. We carried out meta-analyses to test the hypothesis that dysregulation of the HPA axis, as indexed by patterns of diurnal cortisol release, is associated with worse physical performance. Data from six adult cohorts (ages 50-92 years) were included in a two stage meta-analysis of individual participant data.

View Article and Find Full Text PDF

Background: Cross-sectional studies have suggested that elevated cortisol is associated with worse physical performance, a surrogate of ageing. We examined the relationship between repeat cortisol measures over 20 years and physical performance in later life.

Methods: Middle-aged men (45-59 years) were recruited between 1979 and 1983 (Phase 1) from the Caerphilly Prospective Study (CaPS) and re-examined 20 years later at 65-83 years of age (Phase 5).

View Article and Find Full Text PDF

Aging evolves as the result of weakened selection against late-acting deleterious alleles due, for example, to extrinsic mortality. Comparative studies of aging support this evolutionary theory, but details of the genetic mechanisms by which lifespan evolves remain unclear. We have studied aging in an unusual nematode, Strongyloides ratti, to gain insight into the nature of these mechanisms, in this first detailed examination of aging in a parasitic nematode.

View Article and Find Full Text PDF

We investigated the hypothesis that host immunosuppression due to advancing human immunodeficiency virus (HIV) disease favors the direct development of infective larvae of Strongyloides stercoralis, which may facilitate hyperinfection and, hence, disseminated strongyloidiasis. To do this, we sought correlations between the immune status of the subjects and the development of S. stercoralis infections.

View Article and Find Full Text PDF

The extent of genetic variation in fitness is a crucial issue in evolutionary biology and yet remains largely unresolved. In Drosophila melanogaster, we have devised a method that allows the net effects on fitness of heterozygous wild-type chromosomes to be measured, by competing them against two different "balancer" chromosomes. We have applied the method to a large sample of 40 wild-type third chromosomes and have measured fitnesses of nonlethal chromosomes as well as chromosomes bearing recessive lethals.

View Article and Find Full Text PDF

Aging has been characterised in detail in relatively few animal species. Here we describe the aging process in free-living adults of the parasitic nematode Strongyloides ratti. We find that the phenomenology of aging in S.

View Article and Find Full Text PDF

Understanding the processes that drive parasite evolution is crucial to the development of management programs that sustain long-term, effective control of infectious disease in the face of parasite adaptation. Here we present a novel evolutionarily stable strategy (ESS) model of the developmental decisions of a nematode parasite, Strongyloides ratti. The genus Strongyloides exhibits an unusual developmental plasticity such that progeny from an individual may either develop via a direct (homogonic) route, where the developing larvae are infective to new hosts, or an indirect (heterogonic) route, where the larvae develop into free-living, dioecious adults that undergo at least one bout of sexual reproduction outside the host, before producing offspring that develop into infective larvae.

View Article and Find Full Text PDF

Dauer larvae of Caenorhabditis elegans are formed when young larvae experience conditions of low food availability and high conspecific population density; non-dauer, third stage larvae are formed in conditions of plenty. This developmental response to environmental conditions is an example of phenotypic plasticity; that is, an environmentally induced change in phenotype and, as such, a manifestation of a genotype-environment interaction. Extensive variation was found in reaction norms of phenotypic plasticity of dauer formation among wild lines of C.

View Article and Find Full Text PDF

Purpose: Enterocystoplasty provides needed improvement in bladder storage parameters in many patients but it also generates significant morbidity. We evaluated the unusual potential alternative of using the capsule that forms around a standard silicone tissue expander placed perivesically to augment the bladder in dogs.

Materials And Methods: Six mongrel dogs underwent baseline videourodynamics and assessment of serum electrolytes, followed by placement of a 250 to 500 cc perivesical silicone tissue expander.

View Article and Find Full Text PDF