TY - JOUR A1 - Boeker, Sonja A1 - Hermanussen, Michael A1 - Scheffler, Christiane T1 - Dental age is an independent marker of biological age JF - Human biology and public health N2 - Background: Biological age markers are a crucial indicator whether children are decelerated in growth tempo. Skeletal maturation is the standard measure. Yet, it relies on exposing children to x-radiation. Dental eruption is a potential, but highly debated, radiation free alternative.  Objectives: We assess the interrelationship between dental eruption and other maturational markers. We hypothesize that dental age correlates with body height and skeletal age. We further evaluate how the three different variables behave in cohorts from differing social backgrounds. Sample and Method: Dental, skeletal and height data from the 1970s to 1990s from Guatemalan boys were converted into standard deviation scores, using external references for each measurement. The boys, aged between 7 and 12, derived from different social backgrounds (middle SES (N = 6529), low-middle SES (N = 736), low SES Ladino (N = 3653) and low SES Maya (N = 4587). Results: Dental age shows only a weak correlation with skeletal age (0.18) and height (0.2). The distinction between cohorts differs according to each of the three measurements. All cohorts differ significantly in height. In skeletal maturation, the middle SES cohort is significantly advanced compared to all other cohorts. The periodically malnourished cohorts of low SES Mayas and Ladinos are significantly delayed in dental maturation compared to the well-nourished low-middle and middle class Ladino children. Conclusion: Dental development is an independent system, that is regulated by different mechanisms than skeletal development and growth. Tooth eruption is sensitive to nutritional status, whereas skeletal age is more sensitive to socioeconomic background. KW - dental eruption KW - biological age KW - skeletal age KW - growth tempo KW - maturation KW - malnutrition Y1 - 2022 U6 - https://doi.org/10.52905/hbph2021.3.24 SN - 2748-9957 VL - 2021 IS - 3, Summer School Supplement PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Hermanussen, Michael A1 - Scheffler, Christiane T1 - Evidence of chronic undernutrition in late 19th century German infants of all social classes JF - Human biology and public health N2 - 125 years ago, European infants grew differently from modern infants. We show weight gains of 20 healthy children weighed longitudinally from birth to age 1 year, published by Camerer in 1882. The data illustrate the historically prevalent concepts of infant nutrition practiced by German civil servants, lawyers, merchants, university professors, physicians, foresters and farmers. Breastfeeding by the mother was not truly appreciated in those days; children were often breastfed by wet nurses or received bottled milk. Bottle feeding mainly used diluted cow’s milk with some added carbohydrates, without evidence that appropriate amounts of oil, butter or other fatty components were added. French children from 1914 showed similar weight gain patterns suggesting similar feeding practices. The historical data suggest that energy deficient infant formula was fed regularly in the late 19th and early 20th century Europe, regardless of wealth and social class. The data question current concerns that temporarily feeding energy deficient infant formula may warrant serious anxieties regarding long-term cognitive, social and emotional behavioral development. KW - chronic undernutrition KW - breastfeeding KW - historical growth KW - social class KW - translation Y1 - 2022 U6 - https://doi.org/10.52905/hbph2022.2.42 SN - 2748-9957 VL - 2022 IS - 2 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Hermanussen, Michael A1 - Groth, Detlef A1 - Scheffler, Christiane T1 - Human growth data analyses and statistics BT - The 4th Gülpe International Student Summer School JF - Human biology and public health N2 - Students learn by repetition. Repetition is essential, but repetition needs questioning, and questioning the repertoire belongs to the essential tasks of student education. Guiding students to questioning was and is our prime motive to offer our International Student Summer Schools. The data were critically discussed among the students, in the twilight of Just So Stories, common knowledge, and prompted questioning of contemporary solutions. For these schools, the students bring their own data, carry their preliminary concepts, and in group discussions, they may have to challenge these concepts. Catch-up growth is known to affect long bone growth, but different opinions exist to what extent it also affects body proportions. Skeletal age and dental development are considered appropriate measures of maturation, but it appears that both system develop independently and are regulated by different mechanisms. Body weight distributions are assumed to be skewed, yet, historic data disproved this assumption. Many discussions focused on current ideas of global growth standards as a common yardstick for all populations world-wide, with new statistical tools being developed including network reconstruction and evaluation of the reconstructs to determine the confidence of graph prediction methods. KW - Just so stories KW - Summer Schools KW - questioning solutions KW - repetition Y1 - 2022 U6 - https://doi.org/10.52905/hbph2021.3.29 SN - 2748-9957 VL - 2021 IS - 3, Summer School Supplement PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Mumm, Rebekka A1 - Scheffler, Christiane A1 - Hermanussen, Michael T1 - Locally structured correlation (LSC) plots describe inhomogeneity in normally distributed correlated bivariate variables JF - Archives of Public Health N2 - Background The association between bivariate variables may not necessarily be homogeneous throughout the whole range of the variables. We present a new technique to describe inhomogeneity in the association of bivariate variables. Methods We consider the correlation of two normally distributed random variables. The 45° diagonal through the origin of coordinates represents the line on which all points would lie if the two variables completely agreed. If the two variables do not completely agree, the points will scatter on both sides of the diagonal and form a cloud. In case of a high association between the variables, the band width of this cloud will be narrow, in case of a low association, the band width will be wide. The band width directly relates to the magnitude of the correlation coefficient. We then determine the Euclidean distances between the diagonal and each point of the bivariate correlation, and rotate the coordinate system clockwise by 45°. The standard deviation of all Euclidean distances, named “global standard deviation”, reflects the band width of all points along the former diagonal. Calculating moving averages of the standard deviation along the former diagonal results in “locally structured standard deviations” and reflect patterns of “locally structured correlations (LSC)”. LSC highlight inhomogeneity of bivariate correlations. We exemplify this technique by analyzing the association between body mass index (BMI) and hip circumference (HC) in 6313 healthy East German adults aged 18 to 70 years. Results The correlation between BMI and HC in healthy adults is not homogeneous. LSC is able to identify regions where the predictive power of the bivariate correlation between BMI and HC increases or decreases, and highlights in our example that slim people have a higher association between BMI and HC than obese people. Conclusion Locally structured correlations (LSC) identify regions of higher or lower than average correlation between two normally distributed variables. KW - Standard deviation KW - Locally structured standard deviation KW - Locally structured correlation KW - Variance Y1 - 2022 U6 - https://doi.org/10.1186/s13690-021-00748-4 SN - 0778-7367 SN - 2049-3258 VL - 80 PB - Springer Nature BMC CY - Bruxelles ER - TY - JOUR A1 - Rösler, Antonia A1 - Gasparatos, Nikolaos A1 - Hermanussen, Michael A1 - Scheffler, Christiane T1 - Practicability and user-friendliness of height measurements by proof of concept APP using Augmented Reality, in 22 healthy children JF - Human biology and public health N2 - Background: Child growth is a dynamic process. When measured at short intervals, children’s growth shows characteristic patterns that can be of great importance for clinical purposes. Objective: To study whether measuring height on a daily basis using an APP is practicable and user-friendly. Methods: Recruitment took place via Snowball Sampling. Thirteen out of 14 contacted families signed up for a study period of 12 weeks with altogether 22 healthy children aged 3 to 13 years (response rate 93%). The study started with a visit to the family home for the setup of the measurement site, conventional height measuring and initial training of the new measurement process. Follow-up appointments were made at four, eight and 12 weeks. The children’s height was measured at daily intervals at their family homes over a period of three months. Results: The parents altogether recorded 1704 height measurements and meticulously documented practicability and problems when using the device. A 93% response rate in recruitment was achieved by maintaining a high motivation within the families. Contact with the principal investigator was permanently available, including open communication, personal training and attendance during the appointments at the family homes. Conclusion: Measuring height by photographic display is interesting for children and parents and can be used for height measurements at home. A positive response rate of 13 out of 14 families with altogether 22 children highlights feasible recruitment and the high convenience and user-friendliness of daily APP-supported height measurements. Daily APP measurements appear to be a promising new tool for longitudinal growth studies. KW - body height KW - guideline KW - augmented reality KW - daily home-made measurements KW - iPhone KW - APP Y1 - 2022 U6 - https://doi.org/10.52905/hbph2022.2.48 SN - 2748-9957 VL - 2022 IS - 2 PB - Universitätsverlag Potsdam CY - Potsdam ER -