Current research that may be of particular interest to study members
Irregular consumption of energy intake in meals is associated with a higher cardio-metabolic risk in adults of a British birth cohort
Readily available food, particularly of prepared food, and the move from family meals at set times has led to more irregular eating patterns than was seen in the past. There is some evidence that irregular or inconsistent eating is a risk factor for chronic diseases such as cardiovascular disease and diabetes. However research on this topic is limited. In this paper, Dr Gerda Pot, Prof Rebecca Hardy and colleagues set out to explore the association between variations in day-to-day eating patterns and risk factors such as cholesterol, blood pressure and obesity using the 5-day diet diaries filled in by members of the MRC National Survey of Health and Development.
Energy intake in calories for breakfast, lunch, dinner, and between meal snacks was calculated for each day. Individuals with greater day-to-day variation in intake at each meal were defined as having greater eating irregularity scores.
Study members who had greatest irregularity in their energy intake at breakfast and between meals had greater cardio-metabolic risk. There was little association between irregularity of eating at lunch and dinner and the risk factors. These results provide some evidence that eating regular meals may help reduce chronic disease risk, although further research is needed to replicate the findings of this study.
Lifetime Socioeconomic Inequalities in Physical and Cognitive Aging
Several aspects of health functioning decline with advancing age, but older individuals differ considerably in their levels of functioning. One of the key factors that explain differences between individuals is their socioeconomic circumstances. People living in rich areas in England can expect 17 years more disability-free life than those in poor areas. It is possible that socioeconomic circumstances earlier in the life course might also influence functioning in later life. In a paper by Louise Hurst, Dr Mai Stafford and colleagues, published in 2013, they set out to explore this using data from the MRC National Survey of Health and Development.
Nine indicators of physical and cognitive performance were measured by trained nurses when the study members were aged 60 to 64 years. The occupation of the father when the study member was 4 years old and the occupation of the head of the household when the study member was 53 years old were used to capture socioeconomic circumstances. Those born into the most socioeconomically advantaged families had 20% better verbal memory, 13% better lung function, and 11% better balance than those born into the most disadvantaged families. Using a summary of all 9 indicators of physical and cognitive performance, they found that the most advantaged had 66% better functioning than the most disadvantaged.
Those from more disadvantaged backgrounds are more likely to experience socioeconomic disadvantage in adulthood. But even taking account of adult socioeconomic circumstances, differences in physical and cognitive performance by levels of childhood socioeconomic disadvantage remained. These results show that the legacy of poorer childhood circumstances persists at least up to conventional retirement age and affects both physical and cognitive performance. Healthy ageing is about maintaining physical and cognitive function, as well as avoiding death and chronic disease. Public health research and practice should emphasise and monitor physical and cognitive functioning as one approach to reducing socioeconomic inequalities in healthy ageing. Effective initiatives are likely to be long term and to target the many pathways that link socioeconomic circumstances in early life (such as education and body size) to functioning in old age.
Representativeness and response rates in the NSHD
Over 84% of study members living in England, Wales or Scotland helped us with the latest data collection: 2462 completed postal questionnaires, 1690 travelled to a clinical research facility in London, Birmingham, Manchester, Cardiff or Edinburgh, and a further 539 who could not travel to the clinic were seen by a research nurse at home. It was a tremendous effort by all concerned. A paper published in 2013, led by Dr Mai Stafford, investigated the social and health factors that distinguished between the different types of response. One of the things we found was that people who came to the clinic were, on average, healthier that those who were seen at home. This is one of the reasons we are planning a home visit to all study members in the next five years: to make sure we obtain information from as many study members as possible and retain the representativeness of the cohort – a key feature of the NSHD.
Study members often want to know how many of them remain in the NSHD. Of the original sample of 5362, we are still in touch with just over 3000 study members. Around one in ten have emigrated, and similar proportions have either permanently withdrawn or lost contact with the study. One in seven (14%) have died. Please see Mai’s paper for more details.
Clinical disorders in the NSHD at 60-64 years
We have used the wealth of tests and reports from the new data collection and prior histories to classify study members by common clinical disorders, carefully defining two thresholds of severity. A paper, led by Dr Mary Pierce and published in 2012 in PLoS One, shows the distribution and clustering of 15 common clinical disorders (diagnosed and undiagnosed) requiring medical intervention by 60-64 years. These include, for example, diabetes, high blood pressure, obesity and osteoporosis. The main finding was that study members already have two out of these 15 disorders on average; only 15% were disorder free. A cluster of one in five individuals had a higher probability of cardio-metabolic disorders and were twice as likely than others to have been in the poorest health at 36 years. These findings provide an assessment of the met and unmet health care needs in this generation, based on current clinical guidelines or medical consensus. They inform current debates regarding the increasing medicalisation of health and ageing, the implications for health services of widening disease definitions, and the move from a disease-based to a risk-based model of medicine. They indicate that ageing with clinical disorders is likely to be the norm, and that an individual’s ability to adapt and self-manage the changes in health as they age should be included in how we define being healthy at older ages.