Increase In Body Height Research Articles

A new small-bodied hominin from the Late Pleistocene of Flores, Indonesia

Currently, it is widely accepted that only one hominin genus, Homo, was present in Pleistocene Asia, represented by two species, Homo erectus and Homo sapiens. Both species are characterized by greater brain size, increased body height and smaller teeth relative to Pliocene Australopithecus in Africa. Here we report the discovery, from the Late Pleistocene of Flores, Indonesia, of an adult hominin with stature and endocranial volume approximating 1 m and 380 cm3, respectively--equal to the smallest-known australopithecines. The combination of primitive and derived features assigns this hominin to a new species, Homo floresiensis. The most likely explanation for its existence on Flores is long-term isolation, with subsequent endemic dwarfing, of an ancestral H. erectus population. Importantly, H. floresiensis shows that the genus Homo is morphologically more varied and flexible in its adaptive responses than previously thought.

Effects of Surgical Lengthening of the Hamstrings Without a Concomitant Distal Rectus Femoris Transfer in Ambulant Patients With Cerebral Palsy

Eighteen ambulant patients (32 legs) who had undergone fractional lengthening of the medial and lateral hamstrings without rectus femoris transfer underwent pre- and postoperative gait analysis. A significant increase in the amount of knee extension and a decrease in the amount of peak knee flexion in swing were observed. This decrease in knee flexion signified a change towards more normal speed-related values. Dorsiflexion at initial contact decreased significantly for patients who did not undergo a gastrocnemius lengthening (n = 24). Absolute cadence was significantly lower after surgery, but the change in dimensionless cadence was not significantly different. This difference in the outcome between dimensionless and absolute stride parameters can be attributed to the increase in body height after surgery. The clinical significance of these findings is that it is important to recognize that postoperative effects of surgery on gait in children may, in part, be explained by changes in height and not surgery alone.

Determinants of variation in adult body height.

Final body height is achieved as the result of a combination of genetic and environmental factors. The aim of this article is to review past studies on body height that have followed different scientific traditions. In modern Western societies, about 20% of variation in body height is due to environmental variation. In poorer environments, this proportion is probably larger, with lower heritability of body height as well as larger socioeconomic body height differences. The role of childhood environment is seen in the increase in body height during the 20th century simultaneously with the increase in the standard of living. The most important non-genetic factors affecting growth and adult body height are nutrition and diseases. Short stature is associated with poorer education and lower social position in adulthood. This is mainly due to family background, but other environmental factors in childhood also contribute to this association. Body height is a good indicator of childhood living conditions, not only in developing countries but also in modern Western societies. Future studies combining different scientific traditions in auxology are needed to create a more holistic view of body height.

Birth size in relation to age at menarche and adolescent body size: implications for breast cancer risk.

Early age at menarche and tallness are associated with increased risk for breast cancer, and emerging evidence suggests that body size at birth also is positively associated with breast cancer risk in adulthood. We have explored whether this effect of birth size could be mediated by influencing age at menarche or body height during adolescence. Information on age at menarche and adolescent height among 3,343 Norwegian girls 13 to 19 years of age, born at term and whose mothers had no history of gestational disease was individually linked to information on birth weight and length recorded in the national Medical Birth Registry. We related quintiles of birth size, adjusted for length of gestation, to age at menarche and adolescent height and weight, using general linear modeling and Cox regression analyses. In a subsample of the population, we also had information on maternal age at menarche, as well as adult height and body mass index in both parents. We explored whether parental factors confounded the association between perinatal predictors and adolescent outcomes in the daughters. We found that age at menarche tended to occur earlier with decreasing birth weight (p for trend = 0.03), and girls who were thin at birth (i.e., in the lowest quintile of ponderal index) had an earlier age at menarche than other girls (p = 0.02). Weight and length at birth were strongly and positively related to tallness during adolescence (p for trend < 0.001), but ponderal index, indicating obesity at birth, was negatively associated with adolescent height (p for trend = 0.002). Adjustment for parental height, body mass index and maternal age at menarche, in the subsample where this information was available, indicated no substantial confounding by these parental factors. Our results suggest that a positive association between birth size and adult breast cancer is not likely to be mediated by early age at menarche, but possibly by increased body height in adolescence.

Forced expiratory parameters in healthy preschool children (3-6 years of age).

In a group of 173 healthy preschool children 3-6 years of age (body height, 90-130 cm; 102 boys and 71 girls) out of total 279 children examined, maximum expiratory flow-volume (MEFV) curves were recorded in cross-sectional measurements. The majority (62%) of preschool children were able to generate an MEFV curve as correctly as older children. From the curves, maximum expiratory flows at 25%, 50%, and 75 % of vital capacity (MEF(25), MEF(50), and MEF(75)), peak expiratory flow (PEF), forced expiratory volume in 1 sec (FEV(1)), forced vital capacity (FVC), and area delineated by MEFV curve (A(ex)) were obtained. The purpose of the study was to establish reference values of forced expiratory parameters in preschool children suitable for assessment of lung function abnormalities in respiratory preschool children. The values of the studied parameters increased nonlinearly and correlated significantly with body height (P < 0.0001); the correlation was much lower with age. A simple power regression equation was calculated for the relationship between each parameter and body height. A best-fit regression equation relating functional parameters and body height was a power function. Based on the obtained regression equations with upper and lower limits, we prepared tables listing reference values of forced expiratory parameters in healthy Caucasian preschool children, against which patients can be compared. No statistically significant gender differences were observed for MEF(25), MEF(50), MEF(75), PEF, FEV(1), FVC, and A(ex) by extrapolation. The reference values were close to those obtained in our older children. A decline of the ratios PEF/FVC, FEV(1)/FVC and MEF/FVC with increasing body height suggested more patent airways in younger and smaller preschool children.

Urinary Sodium and Potassium Excretion in Idiopathic Hypercalciuria of Children

Background: An increased spot urine Na/K ratio (UNa/K) has been found to be related to urinary stone disease in adults with a history of nephrolithiasis and in children with idiopathic hypercalciuria (HC). However, the respective role played by Na and K excretion in the rise of the UNa/K in growing individuals is not well clarified. Methods: The urinary excretion of Na and K was evaluated in fasting morning and 24-hour urine samples of 37 consecutive children with HC and of 21 previously HC children who were normocalciuric at the time of the study (ExHC). None of them had received any dietary or specific drug prescription. Results: In the HC and in the ExHC group, respectively, the Na excretion was 4 ± (SD) 2.4 and 2.9 ± 1.3 mmol/kg/day (p = 0.009); the K excretion was 1.1 ± 0.4 and 1.2 ± 0.7 mmol/kg/day (p = 0.86); the fasting UNa/K was 3 ± 1.6 and 2.1 ± 1 mmol/mmol (p = 0.044), and the 24-hour UNa/K was 4.2 ± 3.9 and 2.8 ± 1.5 mmol/ mmol (p = 0.045). The 24-hour UNa/K was significantly higher than the fasting UNa/K in both HC (p = 0.002) and ExHC (p = 0.002) subjects. The 24-hour UNa/K significantly increased with age in both HC (p = 0.02) and ExHC (p = 0.015) children. The K excretion significantly decreased with age in HC (p = 0.0001) and ExHC (p = 0.005) subjects, as well as with body weight gain in HC (p = 0.005) and ExHC (p = 0.0001) children and with increasing body height in HC (p = 0.006) and ExHC (p = 0.001) subjects. In neither group was the K excretion significantly related to body mass index Z score nor to height Z score. No significant relation resulted between Na excretion and age, body weight and height, and body mass index Z score and height Z score. Conclusions: HC children have a higher Na excretion as well as a higher fasting and 24-hour UNa/K than ExHC children, but no different K excretion. Meals are accompanied by a significant rise in UNa/K. The rise in UNa/K with age is mostly due to a decrease in K excretion which possibly depends on childhood body growth.

Body height is associated with decreased long-term stroke but not coronary heart disease mortality?

There is disagreement whether shorter persons suffer increased rates of coronary heart disease (CHD) or stroke. Potential mechanisms for such associations are not well understood. We used findings from a cohort study, in which 10 000 Israeli men were followed up, to examine the associations between stature and fatal CHD as well as fatal stroke. The cohort was composed of 10 059 men aged > or = 40 years who were tenured civil servants or municipal employees. They were followed up for mortality over 23 years (1963 to 1986), for a total of 203 452 person-years of follow-up. We divided men by their height, as measured in the baseline (1963) examinations, into quartiles (< or = 162 cm, 163 to 167 cm, 168 to 171 cm, and > or = 172 cm). During the follow-up period, 1098 men died of CHD, and 364 men died of stroke. Height and weight had been measured for 10 034 men, including all but 1 of the deceased. In contrast to the finding of little variation of CHD death rates between different quartiles of body height, a clear significant pattern of declining stroke mortality (slightly reduced by age adjustment) was observed with increasing body height, with rates of 46, 36, 33, and 29 per 1000 men with increasing height quartiles, respectively (P=0.002 for linear trend). The estimated age-adjusted hazard risk of stroke mortality associated with a 5-cm decrement in height was 1.13 (95% CI 1.04 to 1.22). The respective risk associated with being at the shortest quartile versus the tallest one was 1.54 (95% CI 1.13 to 2.10). Adjustment for socioeconomic status, a predictor of stroke in this cohort, for antihypertensive therapy and for established predictors of stroke (blood pressure, smoking, and diabetes) did not alter these findings. Height, a potential strong indicator of nutritional status, may be inversely associated with the long-term incidence of fatal stroke in a way that remains to be elucidated.

Nasal airflow and resistance measured by active anterior rhinomanometry in healthy children and adolescents.

Rhinomanometry allows objective assessment of nasal patency in pediatric patients with nasal and other respiratory problems. However, no reliable reference values are available in the pediatric age group. We measured nasal inspiratory airflow and nasal inspiratory resistance of the right and left nostrils (V'nar, V'nal, Rnar, and Rnal) and total nasal inspiratory flow and resistance (V'na and Rna) at a transnasal pressure of 150 Pa during quiet breathing in healthy children with a closed mouth by using active anterior rhinomanometry. Cross-sectional measurements were done in 192 healthy Caucasian children and adolescents free of nasal or other respiratory diseases (age, 2-19 years; body height, 94-190 cm; 95 boys and 97 girls). The values of V'na, V'nar, and V'nal increased significantly with an increase of body height or age (P<0.0001). Rna, Rnar, and Rnal significantly decreased with an increase of body height and age (P<0.0001). No significant statistical differences were found between boys and girls (P=0.11) or between right and left nostrils (P=0.07). V'nar and Rnar comprised 50.1%, and V'nal and Rnal 49.9%, of total V'na and Rna, respectively. Best-fit regression equations relating rhinomanometric parameters and body height or age were power functions. We obtained reference regression equations with upper and lower limits, and prepared tables listing reference (normal) values of rhinomanometric parameters in healthy pediatric Caucasian patients, against which patients with nasal obstruction can be compared.

Systemic changes in body structure of 17–18-year-old schoolboys

The purpose of this study was to assess the systemic structural changes in the body build of 17-18-year-old schoolboys in the final years of Tartu secondary schools within a height-weight classification dividing anthropometric variables into 5 SD-classes. Weight and height, 9 length, 8 breadth and 2 depth measurements, 16 circumferences and 12 skinfolds were measured. From these 5 length measurements and 53 indices were computed, which characterise the ratios of various parts of the body to body height, to upper and lower limbs' length and body composition. The subjects (n = 253) were divided into five standard deviation classes according to height and weight (Kaarma 1981, 1995). In the first three classes height and weight were proportional: (1) small height--small weight, (2) medium height--medium weight and (3) big height--big weight. In the fourth and the fifth class height and weight were non-proportional. In the fourth class weight was preponderant over height, and in the fifth class height was preponderant over weight. It was proved that a statistical difference exists between the opposite classes--the fourth and the fifth class. It was also revealed that the three proportional classes differ from each other significantly. Increase in body height and weight leads also to an increase in length, breadth and depth measurements, bone thicknesses, circumferences and skinfolds. Rohrer index, body mass index, total percentage of fat by Siri, absolute and relative mass of fat tissue increased from the small to the large class. The relationship of the length, width, and depth measurements, circumferences and bone thicknesses to height remains almost unchanged throughout the proportional classes. These investigations support the position that the whole body model may be reconstructed from body height and weight.

Noninvasive assessment of arterial distensibility in adolescents using the second derivative of photoplethysmogram waveform.

To clarify the clinical usefulness of the second derivative of the waveform of the fingertip photoplethysmogram (SDPTG), we examined the relationship between the pattern of the SDPTG waveform and risk factors related to atherosclerosis in 1,495 boys and girls aged 9-17 years. The fingertip photoplethysmogram and its second derivative wave were automatically recorded from the second digit of the right hand with the subjects lying in a supine position. The SDPTG waveform consisted of a, b, c and d waves in systole and an e wave in diastole. The heights of the a and d waves were measured from the baseline, and the ratio of the height of the d wave to that of the a wave (d/a ratio) was calculated. The d/a ratio had a negative correlation with the systolic (SBP) and diastolic blood pressures (DBP), atherogenic index (AI) and immunoreactive insulin concentrations (IRI) after adjustment for age. Multiple linear regression analysis revealed that the d/a ratio was associated more with body height than the risk factors for atherosclerosis in boys and girls at the growth period. The effect of sex- and height-specific cutoff values of the 10th percentile for the d/a ratio was therefore tested. The results showed that subjects with d/a ratios lower than the 10th percentile had significantly higher SBP, DBP, AI and IRI values compared to those with higher d/a ratios. These findings suggest that differences in the length of the vascular system, which are related to increases in body height, may modify the SDPTG waveform pattern during adolescence. When the body height as well as age and sex is adequately allowed for, the d/a ratio may be useful for the evaluation of arterial distensibility and for identification of individuals at an increased risk of developing atherosclerosis.

Prevalence and trends of obesity among school children in Taiwan--the Taipei Children Heart Study.

In Taiwan, the availability of a high-fat and high-energy diet has steadily risen over the past 30 y, while people have become increasingly sedentary. This lifestyle of poor diet and little physical activity has caused the prevalence of obesity to increase among adults and children. Obesity and associated chronic disease risk factors are becoming important public health issues. The purpose of this study is to evaluate the prevalence and secular trends of being overweight and obese among school children in Taiwan. We conducted a cross-sectional survey among junior high school students in Taipei in 1994 to ascertain a representative distribution of demographic, lifestyle and biochemical characteristics, including several cardiovascular disease risk factors. After multistage sampling of 85 junior high schools in Taipei, we randomly selected 1500 children for this survey. We defined being overweight and obese based on ideal body weight (IBW) criteria. Children are considered to be overweight if their body weight is 110-120% of IBW, and obese if their body weight is greater than 120% of IBW within age- and gender-specific strata. In general, obese children have higher blood pressure, plasma glucose and triglyceride levels and lower high-density-lipoprotein cholesterol levels than normal-weight children. From 1980 to 1994, the mean value of body weight increased significantly over increases in body height (especially among boys). Although the percentage of overweight children remained steady from 1980 to 1994 in both genders, the prevalence and trends of obesity increased significantly, especially among boys and older girls. From this survey we find that in Taiwan from 1980 to 1994 body weight increased dramatically over body height among school children. The prevalence of obesity also increased significantly, especially among boys, while the percentage of overweight children did not vary. Overall, this study indicates that obesity and the adverse effects of being over the ideal body weight is no longer just a problem of Western countries.

Effect of continuous rotary seat pan movements on physiological oedema of the lower extremities during prolonged sitting

Objective: To assess the time-related response of swelling in the lower extremities during static supported sitting compared with sitting in an experimental chair which uses rotary continuous passive motion (RCPM) of the seat pan. Background: The effects of dynamic rotary stimuli on the spine have been tested in previous studies by the authors. Relief of chronic pain was demonstrated, in patients suffering non-specific low back pain. Laboratory tests showed an increase in body height as a result of rotation in the horizontal plane of the seat pan (RCPM), versus a decrease of body height without this stimulation. Stranden investigated the influence of a dynamic sitting pattern of office chairs (Håg Credo 3500, Håg a.s.a. Oslo, Norway) with free-floating tilt mechanism, and found a beneficial effect on the transcapillary fluid balance in healthy control subjects. Method: Ten healthy subjects were measured in two conditions, with and without dynamic stimulation (RCPM) of the seat pan, in 3 h sitting sessions, on successive days. The volume of the lower legs was measured four times, at 1 h intervals, by means of water displacement volumetry (WDV). Results: Significant differences (0.014< p<0.129) in lower leg swelling were found between the static and the dynamic situation. Female subjects showed an increased response in time-related leg swelling and the age of subjects also influenced the results. Conclusion: Dynamic stimulation during sitting has an oedema reducing effect on the lower extremities. Relevance to industry Continuous passive motion must be seen as a promising tool for prevention and therapy, i.e. for the airline industry, professional transport industry and for many more industrial applications.

Werden Kopfmaße von Umweltfaktoren beeinflußt?

In the article the development of skull measurements and head measurements (length and breadth) and of the cephalic index, calculated from these measurements, since the Neolithic period are presented. The results obtained from the historical material are compared with those of living persons. The measurements as well of the skull as of the head show secular changes. The following general trend was found: an increase of body height is connected with a debrachycephalisation and a decrease of body height is connected with a brachycephalisation. It can be emphasized that brachycephalisation/debrachycephalisation are part of the secular trend. Therefore environmental factors are responsible for the described changes of measurements of the skull and the head in a broadest sense.

A peritoneal marker for optimal timing of ventriculo-peritoneal shunt revision in early childhood

The ventriculo-peritoneal shunt placed in a neonate or infant needs revision to lengthen the peritoneal tube at certain times during childhood. The critical time for this revision is not exactly the same between individuals. Furthermore, the level of peritoneal insertion of the shunt tube is often unclear on x-ray films. To plan for and determine the optimal timing of revision, we applied a titanium clip on the peritoneal suture line in three infants as a marker of peritoneal insertion level. During the 31- to 37-month follow-up period, abdominal x-ray clearly demonstrated the peritoneal insertion level in all three patients, allowing accurate determination of the length of the intraperitoneal portion OP) of the shunt tube. The rate of shortening of the length of IP was 20 to 27% of the increase in body height (BH). This technique allows accurate determination of the length of IP and also optimal timing for revision. [Neural Res 1998; 20: 526-528]

The Tromsø Study: body height, body mass index and fractures.

Tall persons suffer more hip fractures than shorter persons, and high body mass index is associated with fewer hip and forearm fractures. We have studied the association between body height, body mass index and all non-vertebral fractures in a large, prospective, population-based study. The middle-aged population of Tromsø, Norway, was invited to surveys in 1979/80, 1986/87 and 1994/95 (The Tromsø Study). Of 16,676 invited to the first two surveys, 12,270 attended both times (74%). Height and weight were measured without shoes at the surveys, and all non-vertebral fractures in the period 1988-1995 were registered (922 persons with fractures) and verified by radiography. The risk of a low-energy fracture was found to be positively associated with increasing body height and with decreasing body mass index. Furthermore, men who had gained weight had a lower risk of hip fractures, and women who had gained weight had a lower risk of fractures in the lower extremities. High body height is thus a risk factor for fractures, and 1 in 4 low-energy fractures among women today might be ascribed to the increase in average stature since the turn of the century. Low body mass index is associated with a higher risk of fractures, but the association is probably too weak to have any clinical relevance in this age category.

Growth promotion by oxandrolone in a girl with short stature and early pubertal development treated with growth hormone and gonadotropin‐releasing hormone‐analogue. A case study

Gonadotropin-releasing hormone (GnRH)-analogues are widely used for treating precocious puberty, and occasionally in short patients and patients with growth-hormone deficiency, in order to delay pubertal development and increase final height. Yet, many of these children only decelerate growth velocity and neither improve in final height nor even in height prediction. As GnRH-analogue treatment dramatically reduces sexual steroid levels, I hypothesized the need for steroid hormone substitution during this treatment. Growth promotion was tried in a healthy girl, with a very unsatisfying height prediction of only 144 cm, using a combination of GnRH-analogue (75 micrograms/kg/4 weeks), plus growth hormone (4 IU/m2/d), plus oxandrolone (1 mg/d). Knemometric measurements of lower leg growth velocity demonstrated that GnRH-analogue alone depresses growth. Additional GH administration only sporadically increases growth velocity, and not until the additional substitution of oxandrolone does growth velocity catch up and return to near pretreatment level. In spite of a 10.3 cm increase in body height during the 15-month period of observation, little bone age progression took place, and height prediction improved from 144 cm to over 149 cm after 9 months, and to 152 cm after 15 months of observation.

BODY HEIGHT, BODY MASS INDEX, AND FATAL HIP FRACTURES

We studied the relations between body height, body mass index (BMI), and fatal hip fractures prospectively in a large, representative population. During the years 1963-1975, a nationwide compulsory mass x-ray examination including standardized height and weight measurements took place in Norway covering all persons age 15 years and older. In the study presented here, we selected women (N = 357,807) and men (N = 316,041) age 50-89 years at screening. We matched the file to the national death register containing causes of death throughout 1991; we defined cases as persons with hip fracture mentioned on their death certificates. During an average follow-up of 16.4 years, we identified a total of 6,087 fatal hip fractures in the study population. There was a distinct inverse relation between BMI and fatal hip fracture, with an age-adjusted relative risk (RR) in the three highest vs the low quartile of 0.68 [95% confidence interval (CI) = 0.63-0.72] in women and 0.57 (95% CI = 0.52-0.62) in men. The risk of fatal hip fractures increased slightly with increasing body height [RR = 1.10 (95% CI = 1.04-1.16) in women and RR = 1.08 (95% CI = 1.01-1.16) in men per 10-cm increase in body height]. This study indicates that low BMI is an important risk factor for fatal hip fractures and that body height has a weak, positive association.

Development of Anaerobic Power for Boys and Girls from Viewpoint of 7-sec Pedalling Exercise

This study investigated the development of level and type of anaerobic power exerted by 7-sec pedalling exercise with special reference to age, sex and body height as an index of growth. Subjects were 92 boys and 90 girls from 4th to 6th grade of elementary school (E 4-E 6) and from 1st to 3rd grade of junior and senior high school (J 1-J 3, S 1-S 3). Pear power/BW and peak frequency of revolution during 7-sec pedalling were measured at torques of 0.04BW, 0.06BW, 0.08BW and 0.1BW. The level of anaerobic power was determined by peak power/BW at each torque. The type of anaerobic power was determined by the coefficients of linear equation representing relationship between torque and peak frequency of revolution. Results were as follows;1) Peak power/BW at each torque increased remarkably from E 4 to J 1 or J 2 for both sexes. Significant sexual difference was recognized at any torque in and after J 2.2) Peak power/BW for both sexes at each torque increased with increasing body height. But peak power/BW of boys compared with girls and individual difference of peak power/BW for both sexes tended to be greater in higher body height and at larger torque. In the latter case, the difference was greater for girls than for boys.3) The type of anaerobic power for both sexes shifted from speed type to strength type during E 4 and J 2 or J 3. The type for boys compared with girls was strength type in and after J 2.4) The type of anaerobic power for both sexes shifted from speed type to strength type with increasing of body height. Sexual difference of the type was not recognized at any body height. Individual difference of the type was greater at any body height for both sexes.These results will be useful findings for establishing measurement and training methods of anaerobic power with special reference to age, sex and body height.

Coactivation of leg reflexes in the stick insect

Each leg of a standing stick insect acts as a height controller. The leg contains several joints. Most of these joints are known to be controlled by feedback loops which are the basis of resistance reflexes (review Bässler 1983). This leads to the question of whether the resistance reflex of the whole leg can be understood as a simple, vectorial sum of the individual reflexes provided by the different joints, or whether additional properties emerge by simultaneous stimulation of several joints. Force measurements were performed while passively moving the middle leg tarsus of a fixed stick insect (Carausius morosus) stepwise to different positions. From the dynamic and static forces the torques developed by each joint were calculated. They were compared with the torques developed when only a single joint was moved by the same amount. The comparison shows that for a large range of positions there are no differences between both situations. Differences occur in two cases. First, the muscle system controlling the coxa-trochanter joint seems to be more strongly excited when the entire leg is moved than when only the one joint is moved. This change increases the linearity of the whole system for small deviations from the zero position. Second, the torque developed by the extensor tibiae system for negative steps (corresponding to increased body height), and the levator of coxa and trochanter for positive steps, decreases rather than increases when the whole leg is moved to extreme positions. This contributes to a decrease in the slope of the force-height characteristic and thus to a more non-linear behaviour of the whole system for the extreme positions. It is well known that the amplification factors of resistance reflexes in the leg show a large variation (Bässler 1972a; Kittmann 1991). Our results indicate that any change of the amplification factor influences the reflexes in all leg joints in the same way.

Prospective study of height, body mass index and risk of breast cancer.

The associations of breast cancer risk with height and body mass index have been examined in 291 cases of breast cancer that occurred among 25,967 Norwegian women during a mean follow-up of approximately 14 years (range 12-16 years). There was an overall increased risk of breast cancer with increasing body height, and the relative risk of women in the fourth quartile of height (mean = 170 cm) was 1.43 (95% confidence limits, 1.18-1.73) compared to women in the lowest quartile (mean = 155 cm), after adjusting for age, parity, age at first birth, and county of residence. Simultaneously, there was an overall inverse relation between body mass index (BMI) and breast cancer risk, which, however, was confined to women 50 years or younger. After adjustment for age, parity, age at first birth, and county of residence, the relative risk of women (less than or equal to 50 years) in the highest quartile of BMI (mean Quetelet = 30) was 0.63 (95% confidence limits, 0.48-0.82), compared to women in the lowest (mean Quetelet = 21). We propose that the lower breast cancer risk in shorter women may reflect caloric restriction during the pre- and peripubertal period, which may affect hyperplastic growth, and lead to a reduced number of breast tissue cells. The negative association with BMI may be related to a lower rate of cell division of breast tissue among obese premenopausal women.