Directional and fluctuating asymmetry among !Kung San and Kavango people of Northern Namibia: The impact of sex and subsistence patterns

Changes in weight status among "Ju/'hoansi" San hunter-gatherers between 1968/69 and 1987-The effects of nutritional transition, sex and age

BACKGROUND

Changes in lifestyle and dietary habits that hunter-gatherer populations have undergone in recent decades have often led to rising obesity rates with disastrous consequences for their health.

OBJECTIVES

The associations between dietary habits and weight status were studied in 238 "Ju/'hoansi" San (93 women and 145 men) aged between 18 and 65 years in northern Namibia in 1987. Weight status was estimated based on the World Health Organization body mass index (BMI) categories, and dietary habits were recorded using food recall methods. Anthropometrics and weight status were compared with those of a sex- and age-matched sample of "Ju/'hoansi" San people collected by Nancy Howell in 1968/69.

RESULTS

Body weight had increased significantly among "Ju/'hoansi" San people from 1968/69 to 1987. The number of underweight people decreased from 1968/69 to 1987. In 1987, most participants (60.9%) were of normal weight. Overweight was found in 1.3% of the women, but not among men. No participants were obese. Less than 4% of the women and less than 2% of the men consumed exclusively traditional hunter-gatherer food. Westernized food products were significantly (p < 0.001) more common among men and younger people. Dietary patterns were significantly associated with weight status. The less traditional the diet, the higher the BMI (p < 0.001).

CONCLUSION

The transition to domestic agricultural and westernized foods was positively associated with increasing BMI. Overweight, however, was still an extremely rare condition in this population in 1987.

Increased dental fluctuating asymmetry is associated with active skeletal lesions, but not mortality hazards in the precontact Southwest United States

OBJECTIVE

This study examines whether individuals with higher dental fluctuating asymmetry (DFA) are frailer than those with lower DFA, by examining whether increased DFA is associated with skeletal lesion formation.

SUBJECTS AND METHODS

150 individuals with permanent teeth and 64 individuals with deciduous teeth. All individuals are Ancestral Puebloans from archaeological sites in modern-day New Mexico. We estimate DFA in three ways: (a) deciduous DFA only, (b) permanent DFA only, and (c) a composite of permanent and deciduous DFA. We analyzed DFA alongside lesion status for cribra orbitalia (CO) and porotic hyperostosis (PH), as well as the presence/absence of enamel hypoplasia (EH). All stress indicators were further analyzed for their impact on mortality hazards.

RESULTS

We find that individuals with active CO and PH lesions have increased DFA, while those with healed lesions have lower DFA. We found no relationship between EH and DFA. Further, DFA alone does not predict individual mortality but CO does.

CONCLUSIONS

Individuals with increased DFA are frailer and therefore, less capable of buffering themselves against perturbations to their health than those with lower DFA. All results indicate that individuals in this study with lower DFA were more successful in buffering themselves against random environmental impacts during childhood. While DFA alone does not predict mortality hazard, its relationship to lesion status (lower DFA in individuals with healed lesions) indicates that it would be a valuable addition to studies of health and stress.

Fluctuating body asymmetry in young Polish women in relation to childhood socioeconomic status

The aim of this study was to analyse the relationship between childhood socioeconomic conditions and body asymmetry in young Polish women. The study measured fluctuating asymmetry (FA), which refers to small random deviations from perfect symmetry in bilaterally paired body structures. Data were obtained from 620 female students aged from 19 to 25 years recruited from Jagiellonian University in Cracow, Poland. The research was carried out in the period from January 2016 to May 2017. A composite fluctuating asymmetry (cFA) of the women was calculated using five bilateral body traits. The lengths and widths of the women’s ears, lengths of their 2nd and 4th digits and wrist widths of the right and left sides of the body were measured twice using standard methodology. The following data were collected in a questionnaire: degree of urbanization of the woman’s place of residence during childhood, number of older siblings, parental education and woman’s dominant hand. The results showed a tendency for FA to fall with an increase in parental education, and to rise with an increase in number of older siblings. The level of FA was significantly lower in women from rural areas than in those from cities. The results of the study show that FA in early adulthood is significantly associated with socioeconomic status during childhood, and confirm that the level of FA in adulthood may be a good indicator of stress factors in the early stages of development.

Asymmetry patterns are associated with body size and somatic robustness among adult !Kung San and Kavango people

Asymmetry of bilateral anatomical structures is widely found in nature. Fluctuating asymmetry, i.e. mostly tiny random deviations from perfect symmetry in bilateral structures, is mainly interpreted within the framework of developmental instability. This interpretation is mainly due to the fact, that higher fluctuating asymmetry is often found in association with various pathological conditions but also from increased stress during somatic development. Directional asymmetry, in contrast, describes a distinct pattern of bilateral variation in a group of individuals, characterized by the tendency to find the larger side mainly at the same side for all individuals. This kind of asymmetry is mostly caused by behavioral lateralization. Somatic stress during development affect not only asymmetry patterns, it is has also an adverse effect on somatic growth. Therefore, the present study tested the hypothesis, that increased asymmetry is associated with decreased body height as well as postcranial length and robustness dimensions. The association patterns between fluctuating as well as directional asymmetry and parameters of somatic growth and robustness are analyzed among 236 !Kung San and 248 Kavango people of Namibia between the ages of 18 and 65 years. Fluctuating asymmetry was determined by ear length and ear breadth. Directional asymmetry was determined by hand length and hand breadth dimensions. Fluctuating as well as directional asymmetry correlated significantly negatively with body height and length dimensions, the correlations however, were weak. The results are interpreted as a corroboration of the theory that developmental stress may increase fluctuating asymmetry but on the other hand may decrease body size.