Social class-specific secular trends in height among 19-year old Polish men: 6th national surveys from 1965 till 2010.

The results presented in this study concern the assessment of the secular trend of body height in 10 % a random national sample (N = 134,224) representing all regions of Poland in 8 homogeneous social groups over 45 years in Poland (1965-2010). Very significant political, social and economic changes in Poland occurred in the period studied. The political revolution that began in Poland at the turn of the 1980s and 1990s dramatically changed the picture of social inequalities in the country. It rapidly transformed (in different directions and to a different degree) the economic situation, working conditions, lifestyles and the prestige of particular social classes and professional groups. A positive secular trend was observed in 19-year-old participants in the period analysed in all homogeneous socio-professional groups, however, with different intensity in each group. The highest body height increases in 1965-2010 were observed in the sons of farmers with post-primary father's education (7.77 cm). The lowest were observed among the sons of professionals, only 5.45 cm. Although social distances between extreme socio-economic groups significantly decreased (from 4.89 cm in 1965 to 2.76 cm in 2010), social gradients of body height, despite the improvement in the standards of living of the entire society remained exceptionally stable and unchanged for nearly half a century.

[Bone mineral density of adults living in the city of Wroclaw compared with the reference ranges]. / Gestosc mineralna koscca obwodowego doroslych mieszkanców Wroclawia na tle wartosci referencyjnych aparatu STRATEC 960.

Certain elements of lifestyles (distinctive for the particular population) are presumed to influence on bone metabolism. This fact results in considerable differences between various populations, concerning both the occurrence of the normal variability of BMD (bone mineral content) among adult and elderly men and women, and also the prevalence of osteopenia or osteoporosis. The purpose of the study was to evaluate the variability of BMD in a group of healthy and occupationally active inhabitants of the city of Wroclaw, Poland (426 men aged 20-59 and 1218 women aged 20-62) and to compare our results with the reference ranges provided by the producer of the Stratec 960 apparatus. Trabecular and total BMD at the distal radius of the nondominant hand were assessed by peripheral Quantitative Computed Tomography (pQCT) using the Stratec 960 apparatus. BMD of Polish men and women significantly differ from the reference ranges of Stratec 960. The unfavourable phenomenon of the greater BMD decline with age, as compared to the standard values provided by the producer of the device, occurred. It should also be stressed that this reduction is more intense with age and it is marked among men older than 36. Taking into consideration the fact, that our material comprises only occupationally active subjects, the revealed differences would be probably greater, if they were evaluated in Polish population as a whole (our sample does not include persons, who are retired from the healthy conditions). Considering those significant discrepancies between our data and the Stratec reference population, one should be careful when using the normative database provided by Stratec for the densitometric diagnosis of osteoporosis among Polish women and men. Additionally the present study reveals that BMD (and its age-related changes during normal aging) is one of the features characteristic for the particular regional population, which is due to inter-populational differences of those elements of lifestyle, which can influence both general health condition and bone mineral density.

Changes in the BMI of Polish conscripts between 1965 and 2001: secular and socio-occupational variation.

OBJECTIVE: To describe changes in the body mass index (BMI) of nationally representative samples of young adult Polish males between 1965 and 2001, and to investigate variation in the incidence of underweight, overweight and obesity between 1965 and 2001 in the young adult males in the context of the socio-political transformation that occurred in Poland since 1989. SUBJECTS: Four 10% nationwide random samples of 29-year-old Polish conscripts examined in 1965, 1986, 1995 and 2001. The conscripts were divided into four socio-occupational groups based on paternal education, occupation and degree of urbanization. MEASUREMENTS: Height, weight and BMI (weight (kg)/height (m2)). RESULTS: The proportion of overweight and underweight young adult males in the population increased between 1965 and 2001. The fraction of underweight decreased only among sons of farmers and entrepreneurs between 1986 and 1995 and then increased in all socio-occupational groups between 1995 and 2001. On the other hand, the proportion of overweight young adults gradually increased in all groups between 1965 and 2001. CONCLUSION: Socio-occupational position of the family is an important factor influencing underweight and overweight in young adult males. This factor apparently operates through a differential distribution of income, which influences components of lifestyle most likely associated with level of habitual physical activity and/or diet.

Changing patterns of social variation in stature in Poland: effects of transition from a command economy to the free-market system?

The aim of this analysis was to examine the effects on stature in two nationally representative samples of Polish 19-year-old conscripts of maternal and paternal education level, and of degree of urbanization, before and after the economic transition of 1990. Data were from two national surveys of 19-year-old Polish conscripts: 27,236 in 1986 and 28,151 in 2001. In addition to taking height measurements, each subject was asked about the socioeconomic background of their families, including paternal and maternal education, and the name of the locality of residence. The net effect of each of these social factors on stature was determined using four-factor analysis of variance. The secular trend towards increased stature of Polish conscripts has slowed down from a rate 2.1 cm per decade across the period 1965-1986 to 1.5 cm per decade between 1986 and 2001. In both cohorts, mean statures increase with increasing size of locality of residence, paternal education and maternal education. The effect of each of these three social factors on conscript height is highly significant in both cohorts. However, the effect of maternal education has increased substantially while that of size of locality of residence and paternal education diminished between 1986 and 2001. These results imply that the influence of parental education on child growth cannot be due solely to a relationship between education and income, but is also perhaps a reflection of household financial management which benefits child health and growth by better educated parents, regardless of level of income. In addition they suggest that, irrespective of whether there are one or two breadwinners in the family, it is the mother, more so than the father, who is principally responsible for the extent to which such management best favours child health and growth. The asymmetry between the importance of maternal as against paternal education for child growth, clearly seen in the 1986 cohort, became more accentuated in 2001, after the abrupt transition from a command to a free-market economy in the early 1990s.

Stature, upward social mobility and the nature of statural differences between social classes.

Stature and educational level achieved were studied in 10 groups of 19-year-old Polish men born in 1967 and examined in 1986. Each group consisted of subjects equated for (1) parental education and occupation, (2) urban-rural residence and (3) number of children in family. It was found that within each group subjects who were secondary school students or graduates were on average taller than their age-mates who by the time of examination had never moved beyond the level of elementary or basic trade school. This result is consistent with the long-debated hypothesis that in industrial societies upward social mobility tends to be selective with regard to body height. Theoretically, such social selection could be expected to inflate the magnitude of social-class differences in stature by adding to them a genetic component. However, a mechanism can be envisaged by which preferential recruitment of taller individuals to upper social strata might indeed be at work and yet produce no differential distribution of genotypes along the social scale.

Body height and upward social mobility.

Stature and education in 214 pairs of adult brothers and 188 pairs of adult sisters were analysed in order to test the hypothesis that in modern stratified societies upward and downward social mobility is selective with respect to body height. Among the 116 male pairs in which the sibs differed in both education and stature, the proportion of pairs in which the taller sib was the better educated (BE) was significantly higher than the proportion of pairs in which the taller sib was the less well educated (LE) of the two. Mean intra-pair difference in stature between the BE and LE brothers was 1.26 cm, and significantly different from zero. In female pairs similar tendencies were noted but deviations from the null hypothesis were not significant. Implications of these findings are discussed.

Social contrasts in the incidence of obesity among adult large-city dwellers in Poland in 1986 and 1996.

The incidence of obesity, defined as the fraction of persons with BMIs exceeding 30-0, was examined in two birth cohorts of 40-50-year-old occupationally active inhabitants of the city of Wroclaw, Poland. In both cohorts and both genders obesity increased monotonically with decreasing position on a three-level educational scale. During the 1986-1996 decade obesity increased dramatically among males with trade school education only; concomitant shifts were much smaller or absent in the college-educated groups. The contrast in obesity between the opposite ends of the educational scale has widened markedly in both genders; and the between-gender gap has declined somewhat.

Secular trends in stature in Poland: national and social class-specific.

Mean statures of Polish 19-year-old males, as estimated from large national random samples of conscripts examined at 10-year intervals, increased from 170.5cm in 1965 to 176.9cm in 1995. The average statural gain of 2.1 cm per decade is rather high compared to other European countries, although not exceptionally so. In addition, secular trends were analysed separately for each of seven selected social groups, each group comprising subjects equated for three social criteria. The rank-order of the seven groups on the statural scale has remained identical throughout the period considered, although the group-specific trends have not been strictly parallel. During the period 1965 1986 there has been a tendency for the groups lowest on the social and statural scale to diminish their statural distance from the social elite, the sons of the large-city intelligentsia, a social group consistently the tallest of all the seven groups considered. However, that tendency for the social gaps to narrow came to a halt during the last, 1986-1995, decade. The present time-lag, in stature, of the group lowest on the social scale, the peasants, behind the social elite amounts to almost 30 years. These findings assume special significance in view of: (1) the high ethnic homogeneity of the population of Poland; (2) the absence in that population of any social-class differences in gene frequencies; and (3) certain peculiarities of Poland's post-war economic and political history.

The stratifying force of family size, urbanization and parental education in socialist-era Poland.

The strength of influence upon statural variation of: (1) the degree of urbanization of the locality of habitat, (2) family size, (3) paternal and (4) maternal educational status was analysed in three generations of 19-year-old Polish conscripts, examined in 1965, 1986 and 1995. Each of the above factors of an individual's social situation was described by a 4-level scale. Each factor was found to exert a highly significant residual effect on stature throughout the three decades considered, even after the effects of other correlated factors were partialed out by three-factor ANOVA. However, the stratifying force of each factor, as expressed by the dispersal of the level-specific main effects around the national mean, has been changing over time. For example, the growth-stunting effect of the condition of coming from a large sibship was dramatic in the 1965 cohort and considerably attenuated in 1986 but ceased to diminish thereafter. The growth-enhancing effect of the condition of being a large-city dweller, initially marked, has almost disappeared; but the growth-stunting effect of the condition of being a rural dweller has remained equally strong across all cohorts. These and other shifts in the relative importance of the social factors, as presumed determinants of family living standards, are described and some explanations attempted.

PIP: This study analyzed the strength of influence upon statural variation, such as: 1) the degree of urbanization of the locality of habitat; 2) family size; 3) paternal education; and 4) maternal educational status. Data was collected in the course of three medical and sociological surveys of 19-year-old Polish conscripts examined in 1965, 1986, and 1995. A 4-level scale described each of the above factors of an individual's social situation. Each factor was observed to apply a highly significant residual effect on stature throughout the three-decades reviewed, even after the effects of other correlated factors were partialled out by three-factor analysis of variance (ANOVA). Findings indicate that in Poland between the late 1940s and the late 1980s, significant inter-generation changes were occurring in the relative importance of the factors of urbanization, parental education, and family size as determinants of family living standards. These patterns should be examined in relation to socioenvironmental aspects, such as wages, real income, handling of family budgets, dietary habits, and city size-dependent availability of principal food items in the local market, periodic food shortages, hygiene standards, and morbidity rates. However, such data are often unreliable and too generalized. Moreover, growth studies should be considered as a potential information source for sociologists, demographers, specialists in public health, and economic historians.

Skeletal maturity at onset of the adolescent growth spurt and at peak velocity for growth in height: a threshold effect?

In 191 Polish boys of the Wroclaw Growth Study, the relationship between skeletal age and chronological age was examined at the onset of the adolescent growth spurt (take-off) and at peak velocity of height growth (PHV). It was found that, at PHV, skeletal age is markedly less variable than is chronological age, but at take-off no such reduction in variability is visible. The following interpretation of this finding is proposed. The onset of the spurt depends, ultimately, upon some maturational processes going on in the hypothalamus and shows little relationship with the advancement of the long bones at that time. Therefore, the spurt can begin at any level of skeletal maturity within the range normally observed at the chronological age at which it happens to begin in the individual. Peak height velocity, on the other hand, is reached when skeletal maturity is sufficiently advanced for testosterone to change its influence upon the bones from one which consists in stimulating cartilage growth to one which consists in stimulating epiphyseal fusion. Therefore, PHV is bound to occur within a range of skeletal maturity much more restricted than that within which take-off can occur.

Retrospective longitudinal growth study of boys and girls active in sport.

Longitudinal records from the Wroclaw Growth Study and the Wroclaw Longitudinal Twin Study were screened for individuals who were active in sport during childhood and adolescence and who were active in sport as young adults. The resulting sample was 25 boys and 13 girls. Heights and weights of the active boys indicated a growth pattern characteristic of early maturers, which was verified in advanced skeletal, sexual and somatic maturation during adolescence. The pubertal progress of active boys suggested no differences in tempo compared to nonathletic boys. In contrast, girls active in sport presented a pattern of growth and maturation characteristic of average maturing individuals, but were taller and heavier than local reference data. Skeletal and chronological ages of active girls did not differ, and the active girls did not differ from local reference data in sexual maturation. PHV, however, was reached later by about one-half of a year. The pubertal progress of girls active in sport did not differ from that of nonathletic girls.

Genetic variance in the pattern of the growth curve for height: a longitudinal analysis of male twins.

Genetic aspects of the pattern of growth and of short-term variations in growth velocity for height were studied in a sample of 44 MZ and 42 DZ twin pairs from the Wroclaw Longitudinal Twin Study. The data consists of serial measurements of height, taken between 8.5 years of age and adulthood. The intra-pair resemblance of the pattern of attained height was quantified by means of the average Euclidean distance coefficient and the coefficient of shape difference, calculated on the raw height-for-age data. Comparison of these resemblance coefficients between the two types of twins indicated that the growth curves of MZ twins are closer to each other, and more similar in shape, than those of DZ twins. The shape of the growth curve was further characterized by a set of biological parameters, derived from Preece Baines model I (PB) fitted to each subject's serial growth data. Genetic analysis of these parameters, according to the model of Christian, Won Kang and Norton (1974), revealed a strong genetic component in the variance of size at particular milestones in the growth process (height at take-off, at peak velocity and at adulthood), and also in the timing of the growth process (age at take-off and at peak velocity). Height velocity at take-off and peak height velocity were also strongly genetically determined. Finally, short-term variations in growth velocity were analysed on the basis of the profiles of the residuals, obtained by the PB fits to each subject's serial measurements of height. Resemblance coefficients were calculated for the profiles of residuals. The results revealed a significantly greater similarity of profile shapes of the residuals in MZ twins than in DZ twins, strongly suggesting that there is a genetic component in the short-term variations of growth velocity.

Social-class gradients in menarcheal age in Poland.

In a sample of approx. 19 000 Polish schoolgirls from the three largest cities of the Upper Silesia conurbation, menarcheal age was studied in relation to parental education (four levels) and father's occupation (12 groups). Menarcheal age tends to increase with decreasing parental education, although the gradient is not steep. When families below a certain level of economic standing are discarded from the best-educated and the least-well-educated groups, mean menarcheal age, surprisingly, decreases much more in the former than in the latter. Mean menarcheal ages for girls from different occupational groups range from 12.82 to 13.30 years and form the following sequence, in increasing order: managers--police--non-technical professionals--engineers, technicians and foremen--skilled industrial workers and small businessmen--unskilled workers--coal-miners. Mean menarcheal age for an occupational group is strongly dependent upon the group's socio-economic status, the latter being defined in terms of parental education, family income, family size, and dwelling conditions. However, daughters of men in the police force mature significantly earlier, and daughters of coal-miners significantly later, than would be expected from each group's rank in socio-economic status. The findings are compared with the results of other recent studies of social gradients in menarcheal age in Poland.

Variation in the body mass index among young adult Polish males between 1965 and 1995.

OBJECTIVE: To investigate whether the incidence of overweight and underweight individuals among young adults showed inter-generation changes or social-class differences in Poland between the mid-1960s and mid-1990s. DESIGN: Comparisons of variation in the body mass index and in height among 19-y-old Polish males drawn from three successive birth cohorts. SUBJECTS: Three 10% nation wide random samples of 19-y-old Polish conscripts, examined in 1965, 1986 and 1995, a total of ca. 80,000 individuals. MEASUREMENTS: Body mass index (weight (kg)/height (m2) and height (m). PRINCIPAL RESULT: There has been during the three decades between the mid-1960s and mid-1990s a gradual and significant increase in the proportion of both 'overweight' and of 'underweight' young males, as well as of the very tall and very short ones in the population. CONCLUSION: The above finding seems intriguing. It may suggest that certain elements of individual lifestyles, those influencing the leanness vs fatness variation among young adults, as well as those affecting growth in height, have tended to become in Poland increasingly diversified in terms of between-family differences, irrespective of social-class differences and of the general nationwide changes in living standards.

Variation in body mass index among Polish adults: effects of sex, age, birth cohort, and social class.

Variation in the body mass index (BMI) among occupationally active inhabitants of one Polish urban center was studied by means of a three-factor ANOVA. The material is cross-sectional and comprises 32,750 men and women aged 22-60 years, examined in five successive surveys between 1983-1999. The factors considered in each sex were: 1) age category, 2) year of examination, and 3) social class. The increase of BMI with age is markedly greater among women than among men. No sustained intergeneration trend towards increased BMI was detectable in either sex. The BMI means rise regularly with decreasing position on the social scale in both sexes, but this effect is much more dramatic in women. The latter finding suggests that the condition of being situated low on the social scale is conducive to growth of fatness with age, markedly more so in women than in men. The absence of a secular trend in BMI means during the period considered contrasts with results reported for a number of other countries. This finding is intriguing, because Poland underwent abrupt and profound socio-economic transformation in the early 1990s.

Interrelationships among certain measures of growth and maturation rate in boys during adolescence.

Relationships among ages at attaining 17 or 21 indices of maturity were considered in a longitudinal sample of 177 Polish boys examined at annual intervals from 1961 to 1972. Maturity indicators included ages at peak velocity for stature, sitting height, leg length and weight; ages at attaining 80%, 90%, 95% and 99% of adult stature; ages at attaining the median skeletal maturity scores (TW-2) characteristic of chronological ages 11, 12, 13, 14, and 15 years; and ages at attaining stages II and IV of genital and public hair development. Age at initiation of the stature spurt (take-off) and ages at eruption of 14, 20 and 26 permanent teeth were ascertained for only 111 boys. All intercorrelations among the developmental indicators were positive. Ordering the correlation matrix gave three clusters: (1) a large central group including age at take-off and ages at all peak velocities, at genital and pubic hair stages II and IV, at attaining 90%, 95% and 99% of adult stature, and at the later stages of skeletal maturity; (2) indices of the tempo of maturation during prepubertal and/or early pubertal stages; and (3) ages at attaining a given number of permanent teeth. Results of a principal components analysis of the ages indicated two principal components, the first accounting for about 77% of the sample variance and the second for about 12%. The first principal component is apparently a general maturity factor, while the second apparently relates to the rate of skeletal maturity during pre-adolescence.

Variation in bone mineral density in adults in Poland: age and sex differences.

The decline of mineral bone density with age can lead in more extreme cases to osteopenia and osteoporosis, and is therefore one of the aspects of ageing with great medical and social significance. With this idea in mind a study of age changes in the trabecular and, separately, the cortical bone density of the radius was carried out in 1218 females and 405 males, aged 22 to 60 years, all occupationally active inhabitants of the city of Wroclaw, Poland. The technique used was the peripheral Quantitative Computed Tomography (pQCT). It was found that in females bone densities remain relatively stable throughout the period between 22 and 40 years. They then begin to decline slowly, with a rapid decline after the age of 55. A distinctly different pattern was found among males, with bone densities reaching peak values, markedly higher than those in females, in the third decade of life. After this age the bone density values begin to decline at a rapid rate, so that by the age of 60 years mean trabecular and cortical densities in males have decreased to levels almost equivalent to females of equal age. In view of the small size of the male samples, especially in the older age classes, the above results should be treated with caution and confirmed using larger samples.

Bone mineral status of Polish men in the course of normal ageing.

Age-related changes in the bone mineral content (BMC) of men are conditioned by both genetic and environmental factors distinctive for particular populations. This results in considerable differences between various populations concerning the prevalence of osteopenia and osteoporosis, and the occurrence of normal variability in BMC among adult and elderly men. The aim of the study was to evaluate the variation of BMC with age in an ethnically homogenous sample of 405 healthy men, aged 20-60 years, all occupationally active inhabitants of the city of Wroclaw, Lower Silesia, Poland. Trabecular and total BMC at the ultradistal radius of the nondominant hand were assessed by peripheral quantitative computerized tomography using the Stratec 960 densitometer. Among Polish men a distinct phase of maximal BMC values (around the age of 30) was distinguished, with a subsequent, quite rapid decline in bone mass. For example, the peak value of trabecular BMC decreased by approximately 13.2% per decade. In Polish men up to 30-34 years old trabecular and total BMC even exceeded reference values by 10%; however, from 35 years onwards their BMC was lower than standard values. This unfavourable phenomenon of BMC decline was augmented with age, and finally BMC values in men aged 55 and over were 30-35% lower than reference values. The significant discrepancies found between the data presented in this study and reference values probably result from inter-populational differences in the lifestyles of healthy ageing men. The results also confirm that bone density (with its age-related changes in the course of normal male ageing) is one of the biological features characteristic of this particular regional population.

Prospective and retrospective longitudinal studies of the growth, maturation, and fitness of Polish youth active in sport.

Results of three longitudinal studies of the growth, maturation and fitness of youth active in sport are summarized. Data include size attained and growth rates for height and body mass, secondary sex characteristics, skeletal age, age at peak height velocity, and two indicators of fitness, peak O2 uptake and power output at a heart rate of 170 bpm (PWC 170). The data for active youth are compared to local reference data and where appropriate to data from other European longitudinal studies. Allowing for variation in methodology and sampling, regular training in sport during puberty and the adolescent spurt does not influence size attained, growth rate, and the timing and progression of somatic, sexual and skeletal maturation in boys and girls. Active and nonactive boys and girls, respectively, do not differ significantly in the mean age at maximum growth in power output at a heart rate of 170 bpm. Boys active in sport, however, have a greater maximal gain in submaximal power output than nonactive boys. Analysis of ontogenetic allometry of peak oxygen uptake and stature and body mass indicate variation between individuals, and between boys of contrasting maturity status.