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PubMed2005

Secular changes are different in distinct subgroups of the growing population.

The change of living conditions in East Germany after the German reunification in 1990 led to intensive secular changes in growth and development. Anthropometric data of height, weight, BMI and thickness of the subcutaneous fat layer are compared from two cross-sectional samples of German children and adolescents aged 6 to 18 years. The first sample was measured around 1989 and the second 10 years later around 1999. Both samples contain children and adolescents from the urban as well as from the rural population. The secular changes reported here are based on the comparison of medians of height, weight, BMI and subcutaneous fat layer thickness calculated for yearly age categories. Subsequently, medians of the 10% border categories are compared. These border categories contain the 10% smallest, lightest, slimmest or leanest subjects and the 10% tallest, heaviest, most corpulent or most obese subjects respectively of a yearly age category. The young generation shifted between 1989 and 1999 to a taller stature in the small as well as in the tall category. The secular pattern of measurements, which mark corpulence, is sex-specific and differs from that of length measurements. In general the light or lean subjects changed only little, however, there are clear age- and sex-specific changes in the upper border categories. Weight and BMI increased markedly in the upper border categories in young preadolescent children, but did not change much in adolescent boys of these category aged 15 and 16 and decreased in adolescent girls. Also the subcutaneous fat layer increased in the upper border category in preadolescent children, but decreased in adolescent boys and girls.

Adolescent↗
PubMed1990

[Secular changes of the mean birth weight and the mean gestational day at an obstetric clinic in Naha].

In our previous study we reported that the secular change of the mean birth weight (MBW) of Okinawa was different from that of Japan as a whole, that is, the MBW of Okinawa was lower, but the annual increase rate of the MBW of Okinawa was larger than that of Japan as a whole. Through analyses using birth records of several obstetric facilities in Naha, we concluded that this phenomenon must be due to the remarkable improvement of the socioeconomical environment of Okinawa. In this report we analyzed secular changes of mean birth weight (MBW) and mean gestational day (MGD) of 15,847 singleton babies born at an obstetric clinic in the city of Naha for the 33 years from 1955 to 1987. To avoid fluctuations of annual changes in MBW and MGD caused by a small number of babies born in a single year, we also used the moving average of three years. In analyzing birth weight we stratified birth weight by sex, parity and the number of gestational weeks. It is considered that birth weight stratified by the number of gestational weeks reflects the intrauterine growth rate of infants. According to our results, both the MBW of infants with 40 gestational weeks, which reflects the intrauterine growth rate, and the MGD increased during the period from the 1950s to the early 1970s in this clinic. On the basis of these results we concluded that the increase of birth weight in this clinic until the early 1970s was due to increases in both the intrauterine growth rate and the gestational period. Our results also show that the mean height of mothers who delivered at this clinic also increased, which might reflect the development of the socioeconomical environment during their childhood. During the period when MBW increased, the economic growth rate of Okinawa was higher than that of other prefectures. From these results we concluded that the MBW can be used as a community health indicator reflecting the total health condition in a given community.

Birth Weight↗
PubMed2006

Examining the evidence for recent secular changes in the timing of puberty in US children in light of increases in the prevalence of obesity.

This report reviews the available evidence from large population studies regarding a secular change in the timing and progress of puberty since 1960 in US children in light of concurrent increases in the prevalence of obesity. There probably was a secular decrease in the median age of onset and progression of genital development in Mexican-American boys and breast development Mexican-American girls in the 1980s and 1990s. The data are insufficient to do more than suggest corresponding trends in black boys and black girls, but there is no evidence of breast changes in white girls. Mean age of menarche decreased by approximately 3 months in US white girls and 5.5 months in US black girls between the late 1960s and approximately 1990. Evidence from a single study indicates the secular changes in age at menarche are consistent with the magnitude of secular change in obesity, although other evidence is equivocal.

Age Factors↗
PubMed1980

[Secular change in the seasonal distribution of menarche in Tokyo].

Secular change in the seasonal distribution of menarche was studied in Tokyo on 17545 females born during 1881 - 1963. The distribution in those born before 1890 showed peak (March-May) and a wide trough during July-October. Occurrences of menarche came to concentrate in April and August after 1890, and also in January after 1950. The distributional pattern has much changed by the period of birth year.

Female↗
PubMed2001

Sex differences in the secular changes in pubertal maturation.

OBJECTIVE: It is a common experience among pediatricians in the industrialized countries that many girls-but many fewer boys-present with secondary sex characteristics at a younger age than normal. This study examines whether there are sex differences in the secular changes toward earlier pubertal maturation. METHODS: The author collected the growth data from various studies performed in Greece in the 20th century (from 1928 to 1995) and estimated the age at peak annual height increment in each study by calculating mean increase in height in each successive year. RESULTS: In all studies, boys presented peak mean annual height increment at 13 to 14 years of age. Girls did not present a discernible peak height increment until the late 1960s; however, thereafter they presented a peak height increment at 11 to 12 years of age. CONCLUSIONS: The data suggest sex differences in the secular changes in pubertal maturation, girls being affected more intensely than boys.

Adolescent↗
PubMedDate not supplied

Secular changes in standing height, sitting height and sexual maturation of Chinese--the Hong Kong Growth Study, 1993.

In 1993 a territory-wide cross-sectional growth survey on 25,000 Chinese children from birth to 18 years was performed in Hong Kong. Compared to the last growth survey in 1963, definite secular changes were observed. There was an increase of final adult standing height of 3.6 cm in boys and 2.7 cm in girls, in which 1.8 cm and 0.5 cm respectively for boys and girls was accounted for by the sitting height. Thus most of the height increase had occurred in the leg length in girls, but in boys only half of it. The height difference was more marked during the pubertal years because secular change had brought about an earlier sexual maturation, including an advancement of median menarcheal age by 0.5 year, coupled with an earlier growth spurt. This paper also provides the first growth standards for Chinese from birth to 18 years, with percentile charts on both standing height and sexual maturation in boys and girls.

Adolescent↗
PubMed2000

Secular changes in relative leg length in post-war Japan.

Longitudinal secular changes of height and estimated leg length (ELL) or subischial leg length of Japanese boys and girls were investigated using data published in "The Statistical Report of the School Health Survey" of the Ministry of Education, Science, Sports and Culture, Japan. A significant trend towards greater relative leg length (long-leggedness) among Japanese children and youth has occurred during the period of about four decades covered by this study. After showing a strikingly consistent trend at all age levels between 6 and 17 years and a dramatic trend during the birth-year age period 1943-1963, the relative growth in leg length has been rapidly slowing or has stopped in both sexes. The relative growth of ELL seemed to be fixed after 11 years in boys and 9 years in girls. Maximum increment ages (MIA), both in height and ELL, were used as estimates of the timing of maximum growth during the adolescent spurt. Regression analysis was used to demonstrate the overall trend patterns of MIA in height and ELL. After removing autocorrelation effects, MIA for height is accelerated by 0.03 year in both sexes, while the MIA in ELL is accelerated by 0.03 year in boys and 0.01 year in girls. Thus, MIA in ELL in girls is occurring earlier but to a smaller extent than in boys. The average maturity difference between boys and girls is 2.07 years in height, but 2.83 years in lower extremity length. Am. J. Hum. Biol. 12:405-416, 2000. Copyright 2000 Wiley-Liss, Inc.

Journal Article↗
PubMed1995

Secular changes in the outcomes to eighteen to twenty-four months of age of extremely low birth weight infants, with adjustment for changes in risk factors and severity of illness.

OBJECTIVES: To analyze secular changes in the rates of death and of major impaired outcome in surviving outborn infants who weighted < or = 800 gm at birth and were admitted in 1980 to 1989, with adjustment for changes in risk factors and severity of illness around the time of birth; and to identify changes in these factors that might explain changes in outcomes. DESIGN: Retrospective cohort study with follow-up to a minimum of 18 months of postterm age. After preliminary screening, multivariate models of association between risk/severity of illness factors and outcomes were constructed, validated, and used to adjust outcomes (death and major impairment to 18 to 24 months of age). SETTING: Regional neonatal intensive care unit for referral of "outborn" infants. PATIENTS: Two hundred eighty-seven consecutively admitted infants who weighted < or = 800 gm at birth (97% follow-up). RESULTS: The death rate during the 1980s did not fall significantly (p adjusted for risk factors = 0.115). The major impairment rate fell (odds ratio, 0.24 (95% confidence interval, 0.10, 0.60); p = 0.002, adjusted for delivery route and respiratory failure measures), mainly because of a reduced rate of blindness, not attributable to cryotherapy. The risk factors that improved and were possibly related to the reduced impairment rate were blood pH and glucose concentration, and serum sodium concentration in the first 48 hours of life. CONCLUSIONS: Despite an increasing selection for referral of less mature and more severely ill outborn babies near the "limit of viability," and despite more aggressive care, the rate of major impairment fell significantly during the 1980s. This trend was enhanced by adjustment for severity of illness. The fall was attributable to a reduced rate of blindness, and was associated with evidence of improved control of physiologic balance after birth.

Apgar Score↗
PubMed2003

Secular changes in tooth size and dental arch dimensions in the mixed dentition.

Secular changes in the mixed dentition were studied. Permanent tooth size and dental arch dimensions were examined in Norwegian children born in the 1960s and 1980s, Swedish children born in the 1960s and 1980s, Norwegian Sami children born in the 1980s, and a sample of Norwegian skulls dating from the 14th to the 19th century. The Norwegian Sami children were nomadic in the summertime. A sample of pigs was studied before and after a maceration process to determine what dimensional changes might occur in such a process. A shrinkage of 0.3%-1.7% was found. This information was used when the skulls were compared with the modern groups. Lateral dental arch lengths were shorter in the children born in the 1960s compared with the children born in the 1980s. This was a result of the higher prevalence of caries in the second deciduous molars in the 1960s groups. Children who had lost a deciduous canine prematurely were found to have smaller dental arch perimeters. When compared with other data, this was blamed on a pre-existing crowding. Permanent tooth size was smaller in the skulls compared with the modern groups. Improved nutrition is considered to be the main reason for the difference. Relative dental arch space differed in the group born in the 1960s from that in the other groups, indicating a greater prevalence of crowding in the former. Relative dental arch space in the skulls and in the group born in the 1980s was similar. A more traditional way of living, as practised by the Sami group in this thesis, was not favorable for relative dental arch space. The transverse intermaxillary relation in boys changed from the 1960s to the 1980s, which indicated that the 1980s group ran a greater risk of developing a posterior cross-bite. Before the same conclusion could be made in the girls, the mesial drift of the first permanent molars had to be corrected for, because of a higher prevalence of caries in the 1960s group. The sex-pooled analysis of the skulls and the contemporary groups revealed that the risk for developing a posterior cross-bite in the 1980s group was greater than in the skulls. The skulls had smaller arch depths than the modern groups.

Adolescent↗
PubMed1996

Secular changes of body height and mass in the children and adolescents of Lódź.

The report illustrates secular changes in the development of body height and mass in Lódź school children and youths in a period of time covering 65 years between 1930-1994. The lowest values of both traits were found in the early post-war period (1948-1949) increasing gradually until the end of the seventies. From that time the secular trend diminished successively, restraining completely in the last years (1992-1994). This seems to be connected with the economic crisis of the eighties in Poland, and the deep transformation of socio-economic relations in the last several years. According to the secular changeability values, the rate of that process in relation to younger groups of children increases considerably from the 12th year of life. The biggest changes (in centimeters and kilograms per decade) can be observed in the age of 15 and 16 years. Usually more distinctive variableness is apparent in boys than in girls.

Adolescent↗
PubMedDate not supplied

Secular change in age at menarche in rural Oaxaca, southern Mexico: 1968--2000.

OBJECTIVE: To evaluate secular change in the age at menarche between 1978 and 2000 in residents of a rural Zapotec-speaking community in Oaxaca, southern Mexico, using status quo and retrospective methods. MATERIALS AND METHODS: Status quo menarcheal status of girls 9-18 years of age in 1978 (n= 101) and 2000 (n=238) and retrospective ages at menarche of adult women 19+ years of age in 1978 (n = 228) and 2000 (n = 246) were obtained via interview. Probit analysis was used to estimate median ages at menarche and 95% confidence intervals (CI) for the status quo data. Analysis of variance and linear regression was used to compare the retrospective data across surveys. RESULTS: The median ages at menarche of adolescents are 14.8+/-1.2 years (0.24 year, 95% CI 14.2-15.4 years) in 1978 and 13.0+/-1.0 years (0.10 year, 95% CI 12.7-13.3 years) in 2000. Age at menarche has declined by 1.8 years over about 23 years, 0.78 year/decade (95% CI = 0.65-0.91 year/decade). Recalled ages at menarche do not differ by age group in the 1978 survey, but differ significantly by age group in the 2000 survey (p <0.001). Within the 2000 survey, the two youngest age groups (< 29, 30-39 years) do not differ, but attain menarche earlier than women in the four older age groups (p < 0.05), who do not differ from each other in age at menarche. The estimated rates of secular decline in age at menarche in adult women vary between 0.38 and 0.42 years/decade (0.26-0.56 year/decade). CONCLUSIONS: There is a major secular decline in the age at menarche of adolescent girls and young adult women between 1978 and 2000. The estimated rate of decline in adult women is about one-half of that in adolescent girls. The secular decline in age at menarche is consistent with corresponding secular gains height, sitting height and estimated leg length of children and adolescents in the community; corresponding secular gains are smaller in young adults 19-29 years.

Adolescent↗
PubMed1988

Secular changes in the angle of divergence of the first two metatarsals in the Japanese.

This investigation concerns secular changes of the intermetatarsal M1-M2 angle in the foot of Japanese, from the prehistoric Jomon period to early modern times. The divergence of the first metatarsal from the second in both sexes in the reconstructed tarsometatarsal bones gradually decreased during this period. In addition, the difference between sexes or sides in each period is small and statistically insignificant. With time, the first metatarsocuneiform angles, in both sexes, also decreased in parallel with the reduction of the intermetatarsal M1-M2 angle, while the second metatarsocuneiform angles in both sexes increased. Both may play a role in decrease of the intermetatarsal M1-M2 angle. A conspicuous angular divergence of the first metatarsal from the second one occurred in comparatively recent times. This change would be accelerated by modification in life-style, together with the effects of footwear.

Anthropology, Physical↗
PubMed2005

Secular changes in head dimensions of Japanese adult male students over eight decades.

The aim was to study secular changes in head dimensions of Japanese adult males. The subjects were all of Japanese birth and Japanese ancestry. The age range of the subjects was between 18 and 25 years. Four head measurements were taken: head length, head breadth, head height and head circumference. In addition, stature and body weight were also measured. All measurements were made by one observer (Fumio Ohtsuki) from 1998 to 2001. The present sample was compared with the series taken between 1910 and 1917 of Matsumura (J Fak Sci Imp Univ Tokyo Sec 1 (1925) 1) and the one measured in 1965 of Morita and Ohtsuki (Hum Biol 45 (1973) 151). The present study demonstrated the presence of larger means for head length, head breadth and cephalic index in the current sample than in their predecessors of about 35-85 years ago. Also, the present series displayed larger head circumference than that of the Morita and Ohtsuki series. Using ANOVA, head length and head breath showed significant (p<0.01) differences among all birth-year cohorts from 1978 to 1983 of the current sample. Head height, head circumference and cephalic index did not display significant differences. However, the slope of the regression line indicated that all measurements as well as the cephalic index showed slightly decreasing tendencies during the investigated period. These results suggest that brachycephalization has been occurring for approximately about 35-85 years in adult Japanese males, but the change seems to have become reversed slightly during the period covered by the present sample.

Adolescent↗
PubMedDate not supplied

Secular change in growth over one decade (1980-1990) in Shanghai infants.

The aims of this study were to describe secular changes in body size in Shanghai infants, to compare the growth pattern between Shanghai children and Swedish children, and to explore the association of growth rate with parental body size, feeding practice and child health status. The study series consisted of 6,018 longitudinally followed full-term children, born between 1st January 1980 and 31st December 1990 in Fenglin Community, Shanghai. The data clearly show a positive secular trend in growth in Shanghai over the decade of observation; at 12 months, the mean increase in weight and length were 0.32 kg and 0.64 cm, and at 24 months they were 0.54 kg and 1.29 cm. The general growth pattern observed in the children in comparison with the Swedish reference was of fast growth in the first few months of life, and faltering between 9 and 24 months of age. Age at introduction of solid food, weaning age and parental body size were related to growth velocity in the first two years. There was little cumulative effect of diarrhoea on growth in the first two years of life.

Body Height↗
PubMed1987

Some secular changes in body height and proportion of Japanese medical students.

Anthropometric dimensions of 738 medical students at Kyushu University in Japan were analyzed to determine secular changes of height and body proportions during a 20-year period. Since 1961, means of standing height, leg length, and ratio of leg length to standing height have increased, although the rate of increase from 1971 to 1981 has been rather slow. On the contrary, the mean sitting height X 100/standing height has declined during this same period. Compared with data on the Japanese general population, the medical students were considerably taller, but the difference has decreased.

Adult↗
PubMed1979

Secular change in the variability of temperature.

The mean temperatures for January, April, summer and October at New Haven, Connecticut, for 1781-1970 were analyzed for evidence of a secular change in several indices of variability. The January-July difference decreased significantly. Although the standard deviation (SD) of the summer temperature within decades decreased significantly, the SDs of January, April, and October did not, and none of the SDs were correlated with means. The SD about trends within decades was not correlated with the magnitude of the trends except in April. There was no significant trend in the January-to-January persistence during the 19 decades.

Journal Article↗