Accuracy of self-reported anthropometric measures - Findings from the Finnish Twin Study.

OBJECTIVE: To determine the accuracy of self-reported height, weight, body mass index (BMI) and waist circumference (WC) compared to the measured values, and to assess the similarity between self-reported and measured values within dizygotic (DZ) and monozygotic (MZ) twin pairs. METHODS: The data on self-reported and measured height, weight and WC values as well as measured hip circumference (HC) were collected from 444 twin individuals (53-67 years old, 60% women). Accuracies between self-reported and measured values were assessed by Pearson's correlation coefficients, Cohen's kappa coefficients and Bland-Altman 95% limits of agreement. Intra-class correlation was used in within-pair analyses. RESULTS: The correlations between self-reported and measured values were high for all variables (r=0.86-0.98), although the agreement assessed by Bland-Altman 95% limits had relatively wide variation. The degree of overestimating height was similar in both sexes, whereas women tended to underestimate and men overestimate their weight. Cohen's kappa coefficients between self-reported and measured BMI categories were high: 0.71 in men and 0.70 in women. Further, the mean self-reported WC was less than the mean measured WC (difference in men 2.5cm and women 2.6cm). The within-pair correlations indicated a tendency of MZ co-twins to report anthropometric measures more similarly than DZ co-twins. CONCLUSIONS: Self-reported anthropometric measures are reasonably accurate indicators for obesity in large cohort studies. However, the possibility of more similar reporting among MZ pairs should be taken into account in twin studies exploring the heritability of different phenotypes.

The CODATwins Project: The Current Status and Recent Findings of COllaborative Project of Development of Anthropometrical Measures in Twins.

The COllaborative project of Development of Anthropometrical measures in Twins (CODATwins) project is a large international collaborative effort to analyze individual-level phenotype data from twins in multiple cohorts from different environments. The main objective is to study factors that modify genetic and environmental variation of height, body mass index (BMI, kg/m2) and size at birth, and additionally to address other research questions such as long-term consequences of birth size. The project started in 2013 and is open to all twin projects in the world having height and weight measures on twins with information on zygosity. Thus far, 54 twin projects from 24 countries have provided individual-level data. The CODATwins database includes 489,981 twin individuals (228,635 complete twin pairs). Since many twin cohorts have collected longitudinal data, there is a total of 1,049,785 height and weight observations. For many cohorts, we also have information on birth weight and length, own smoking behavior and own or parental education. We found that the heritability estimates of height and BMI systematically changed from infancy to old age. Remarkably, only minor differences in the heritability estimates were found across cultural-geographic regions, measurement time and birth cohort for height and BMI. In addition to genetic epidemiological studies, we looked at associations of height and BMI with education, birth weight and smoking status. Within-family analyses examined differences within same-sex and opposite-sex dizygotic twins in birth size and later development. The CODATwins project demonstrates the feasibility and value of international collaboration to address gene-by-exposure interactions that require large sample sizes and address the effects of different exposures across time, geographical regions and socioeconomic status.

A multifactorial fall prevention programme in home-dwelling elderly people: a randomized-controlled trial.

OBJECTIVES: To describe the implementation and the effects of a multifactorial fall prevention trial on the specified risk factors of falling, incidence of falls and injurious falls, and on specified secondary outcome measures; to describe the design of the study and to assess the success of randomization. STUDY DESIGN: Randomized-controlled trial. METHODS: Recruitment started in March 2003 and lasted until the end of January 2005, when a total number of 591 participants was reached. Participants were randomized into two age groups (65-74 years and 75 years and over), then into an intensive multifactorial risk-based prevention programme or into a one-time counselling on fall prevention. The intervention included individual geriatric assessment, guidance and treatment, individual guidance on fall prevention, physical exercise in small groups, psychosocial group activities, lectures, home-exercises and home hazards assessment. RESULTS: A total of 293 people were randomized into the 1-year prevention programme and 298 into the control condition. The mean age was 73.5 years in both groups; 84% of the participants were women. The groups were well balanced at baseline in relation to risk factors of falls, and the only statistically significant difference was found in the amount of regularly taken medicines, which was significantly lower in the control group: mean 3.7 (SD 3.0) vs. 4.2 (SD 3.1), P=0.028. CONCLUSIONS: Participants were successfully randomized into a multifactorial fall prevention trial.