Bergmann’s rule is a “just-so” story of human body size

Carl Bergmann was an astute naturalist and physiologist. His ideas about animal size and shape were important advances in the pre-Darwinian nineteenth century. Bergmann’s rule claims that that in cold climates, large body mass increases the ratio of volume-to-surface area and provides for maximum metabolic heat retention in mammals and birds. Conversely, in warmer temperatures, smaller body mass increases surface area relative to volume and allows for greater heat loss. For humans, we now know that body size and shape are regulated more by social-economic-political-emotional (SEPE) factors as well as nutrition-infection interactions. Temperature has virtually no effect. Bergmann’s rule is a “just-so” story and should be relegated to teaching and scholarship about the history of science. That “rule” is no longer acceptable science and has nothing to tell us about physiological anthropology.

Association of height loss and cardiovascular disease: Data from a large Korean cohort

Background

Height declines with age, and its degree differs among individuals. Despite epidemiologic evidence for the inverse relationship between adult height and cardiovascular disease (CVD) incidence, the clinical significance of height loss in CVD remains to be elucidated. Therefore, this study investigated the association between height loss and CVD incidence.

Methods

In total, 127,573 Korean participants were enrolled; their heights were monitored from 2002 to 2011. The annual height loss (cm/year) was the difference between the first and last height measurements within the observation period divided by the number of years. The participants were classified as Group 1 (height loss: <0.3 cm/year; n = 102,554), Group 2 (height loss: 0.3– < 0.6 cm/year; n = 17,324), or Group 3 (height loss: ≥0.6 cm/year; n = 7,695).

Results

The cumulative major adverse cardiac and cerebral event (MACCE: cardiac death, non-fatal myocardial infarction, and unplanned hospitalization for heart failure or stroke) incidence rate was 3.6% for Group 1, 4.5% for Group 2, and 5.2% for Group 3. Group 2 (hazard ratio [HR] = 1.27, 95% confidence interval [CI] = 1.17–1.37) and Group 3 (HR = 1.46, 95% CI = 1.32–1.62) had a significantly higher incidence of MACCE than Group 1. In the model adjusted for age, sex, comorbidities, income level, body mass index, smoking, and drinking status, the MACCE risk was higher in Group 2 (HR = 1.11, 95% CI = 1.07–1.20) and Group 3 (HR = 1.25, 95% CI = 1.13–1.39) than in Group 1.

Conclusion

The degree of height loss was independently associated with CVD occurrences in the Korean population.

Effects of Routine Health Care Combined with Oral Vitamin D on Linear Growth in 5-Year-Old Children

Objective

The aim is to evaluate the effects of routine health care combined with oral vitamin D on linear growth in 5-year-old children.

Materials and Methods

The 5-year-old children who received routine health care in Shiyan Maternal and Child Health Care Hospital from January 2019 to January 2021 were retrospectively analyzed. They were divided into the supplement group and the non-supplement group according to whether or not they received oral vitamin D, and reasons for not taking oral vitamin D and its influence on children's linear growth were analyzed.

Results

A total of 368 children were enrolled, including 228 children in the supplement group, accounting for 61.96%. The analysis of the influencing factors of vitamin D supplementation showed that the proportion of children with well-educated parents and living in cities and towns was higher (all P < 0.05). Comparing the general situation of children in the two groups, it was found that the height, weight, and head circumference of children in the supplement group were notably higher than those in the non-supplement group (all P < 0.05). At age 4 and 5, the height of the supplement group was significantly higher than that of the non-supplement group (all P < 0.001). Linear analysis showed that the relationship between height and age in the supplement group was Y (height, cm) = 10.07 × X (age, years) + 61.18, while that in the non-supplement group was Y (height, cm) = 8.296 × X (age, years) + 62.81, with significant difference (all P < 0.05). Serum 25-hydroxyvitamin D concentration in the supplement group was significantly higher than that in the non-supplement group, and the proportion of children ≥75 nmol/L was evidently higher than that in the supplement group (all P < 0.05). In addition, the incidence of vitamin D-related hypercalcemia in the supplement group was significantly higher than that in the non-supplement group (all P < 0.05).

Conclusion

There are still more children without vitamin D supplement, which is closely related to their parents' education background and place of residence. Additionally, vitamin D supplementation can promote growth and improve 25-hydroxyvitamin D levels in children, but with the risk of related complications.

Infant Anthropometry and Growth Velocity Before 6 Months are Associated with Breastfeeding Practices and the Presence of Subclinical Mastitis and Maternal Intestinal Protozoa in Indigenous Communities in Guatemala

BACKGROUND

The possibility that maternal health status and breastfeeding practices contribute to growth faltering before 6 mo is underexplored.

OBJECTIVES

This longitudinal study investigated whether indicators of subclinical mastitis (SCM) and breast inflammation, maternal fecal-oral contamination, and/or breastfeeding practices were associated with infant anthropometry or growth velocity before 6 mo.

METHODS

Indigenous Mam-Mayan mother-infant dyads (n = 140) were recruited. Breast milk was collected at early (<6 wk) and established (4-6 mo) lactation when maternal and infant anthropometry were measured. Milk Na:K ratio as an indicator of SCM and concentrations of 4 proinflammatory cytokines were measured. Maternal stool samples were examined for the presence of intestinal parasites including nonpathogenic protozoa (Endolimax nana, Iodamoeba bütschlii, Entamoeba coli, Blastocystis hominis). Questionnaires characterized breastfeeding and hygiene practices. Multiple linear regression identified factors associated with infant growth attainment [weight-for-age z-score (WAZ), length-for-age z-score (LAZ), and head circumference-for-age z-score (HCAZ)] and growth velocity (expressed as change per day from early to established lactation). Multiple logistic regression identified factors associated with increased odds of underweight, stunting, and low head circumference at both lactation stages.

RESULTS

A higher Na:K ratio, individual nonpathogenic protozoa, and specific breastfeeding and hygiene practices were associated with impaired growth before 6 wk and at 4-6 mo in exclusively breastfed infants. Growth velocity for weight was inversely associated with Entamoeba coli but cranial growth was associated positively with Iodamoeba bütschlii whereas feeding colostrum in early lactation was protective and decreased the odds of an HCAZ < -2 SD. Finally, the presence of SCM in early lactation increased the likelihood of both WAZ < -2 SD and LAZ < -2 SD by 6 wk.

CONCLUSIONS

Prevention of SCM can improve early infant weight, but measures that promote the feeding of colostrum and reduce exposure to fecal-oral contamination might be required to minimize infant growth faltering in breastfed infants.

Fear, violence, inequality, and stunting in Guatemala

BACKGROUND

Stunting is defined by the public health community as a length- or height-for-age <-2 SD of a growth standard or reference and is claimed to be caused by poor nutrition, repeated infection, and inadequate psychosocial stimulation.

MATERIAL AND METHODS

Stunting is common at all income levels in middle- and low-income countries. At the higher income levels, stunting is unlikely to be caused by nutrient deficiency or infectious disease.

RESULTS

In Guatemala, 17% of <5-year-olds in the highest family income quintile are stunted. Guatemala has a history of violence from armed conflict, current-day social and economic inequalities, government corruption, and threat of kidnapping for the wealthiest families.

DISCUSSION AND CONCLUSION

The high level of persistent violence creates an ecology of fear, an extreme range of inequalities in Social-Economic-Political-Emotional resources, and biosocial stress that inhibits skeletal growth and causes stunting for people of all income levels.

Height Is Associated with Dyslipidemia in Korean Premenopausal Women: Data from the Korea National Health and Nutrition Examination Survey

BACKGROUND

The association between height and cardiovascular disease (CVD) has been reported in epidemiological studies for decades; however, the mechanism for this relationship is still unclear. We previously reported that dyslipidemia was associated with adult height in Korean men without CVD.

OBJECTIVES

This study explored the potential -relationship between height and dyslipidemia in premenopausal women.

METHODS

This study used data from the 2007-2016 Korea National Health and Nutritional Examination Survey (KNHANES). We identified 16,361 premenopausal women aged ≥19 years without a history of CVD (myocardial infarction/stroke) or cancer. Fasting total cholesterol, triglyceride, and high-density lipoprotein cholesterol (HDL-C) levels were measured. Dyslipidemia was further classified as hypercholesterolemia (total cholesterol level ≥240 mg/dL or treatment with lipid-lowering medications), hypertriglyceridemia (triglyceride level ≥200 mg/dL), and low HDL-C (HDL-C level <40 mg/dL). Subjects were divided into four groups by their height (<155, 155-159.9, 160-164.9, and ≥165 cm), and the prevalence of dyslipidemia was compared.

RESULTS

Multiple regression analysis revealed that short premenopausal women had a higher likelihood of hypercholesterolemia (ptrend = 0.002), hypertriglyceridemia (ptrend = 0.010), and low HDL-C (ptrend = 0.002) when adjusted for age, comorbidities, waist circumference, health-related habits, and economic status.

CONCLUSION

There was a dose-dependent correlation between adult height and adverse lipid profile in premenopausal Korean women who did not have CVD. This finding could serve as further evidence that dyslipidemia can be a link between shortness and CVD.