Verschiedenes » Zwillingsstudien

Ein Problem bei vielen Interventionen ist, dass wir nicht wissen, wie wirksam sie wirklich sind. Deshalb hatte ich die Idee, Zwillingsstudien anzuschauen.

Facial changes caused by smoking: a comparison between smoking and nonsmoking identical twins

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Smoking twins compared with their nonsmoking counterparts had worse scores for upper eyelid skin redundancy, lower lid bags, malar bags, nasolabial folds, upper lip wrinkles, lower lip vermillion wrinkles, and jowls. Lower lid hyperpigmentation in the smoking group fell just short of statistical significance. Transverse forehead wrinkles, glabellar wrinkles, crow's feet, and lower lip lines accentuated by puckering did not have a statistically significant differences in scores. Among twins with greater than 5 years' difference in smoking duration, twins who had smoked longer had worse scores for lower lid bags, malar bags, and lower lip vermillion wrinkles.

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https://pubmed.ncbi.nlm.nih.gov/23924651/

Factors contributing to the facial aging of identical twins

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Four-point higher body mass index was associated with an older appearance in twins younger than age 40 but resulted in a younger appearance after age 40 (p = 0.0001). Eight-point higher body mass index was associated with an older appearance in twins younger than age 55 but was associated with a younger appearance after age 55 (p = 0.0001). The longer the twins smoked, the older they appeared (p < 0.0001). Increased sun exposure was associated with an older appearance and accelerated with age (p = 0.015), as was a history of outdoor activities and lack of sunscreen use. Twins who used hormone replacement had a younger appearance (p = 0.002). Facial rhytids were more evident in twins with a history of skin cancer (p = 0.05) and in those who smoked (p = 0.005). Dark and patchy skin discoloration was less prevalent in twins with a higher body mass index (p = 0.01) and more common in twins with a history of smoking (p = 0.005) and those with sun exposure (p = 0.005). Hair quantity was better with a higher body mass index (p = 0.01) although worse with a history of skin cancer (p = 0.005) and better with the use of hormones (p = 0.05).

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https://pubmed.ncbi.nlm.nih.gov/19337100/

Einige Puntke: Ein etwas höherer BMI wirkte ab 40 ein jüngeres Aussehen, Raucher sahen älter aus, Sonnenexposition bewirkte ein älteres Erscheinungsbild, Hormonersatztherapie hat das Aussehen verjüngt.
Hier wird die Studie schön mit Bildern erklärt: https://www.oneaesthetics.com/post/the-t...te-facial-aging

Objective assessment of facial skin aging and the associated environmental factors in Japanese monozygotic twins

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Among the twin pairs who provided answers to the questions regarding history differences in medical interviews, the twins who smoked or did not use skin protection showed significantly higher facial texture or wrinkle scores compared with the twins not exposed to cigarettes or protectants (P = 0.04 and 0.03, respectively). The study demonstrated that skin aging among Japanese MZ twins, especially in terms of facial texture, was significantly influenced by environmental factors. In addition, smoking and skin protectant use were important environmental factors influencing skin aging.

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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4141746/

Spricht wieder für Sonnenschutz und gegen Rauchen. Interessanterweise haben Alkoholkonsum und Hormonersatztherapie hier keine starken Unterschiede bewirkt:

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There were no significant intrapair differences in the other environmental factors, namely alcohol consumption, hormone replacement therapy, sun exposure history, marital status, medical history, or BMI.

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Kicking Back Cognitive Ageing: Leg Power Predicts Cognitive Ageing after Ten Years in Older Female Twins

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Leg power predicts both cognitive ageing and global brain structure, despite controlling for common genetics and early life environment shared by twins. Interventions targeted to improve leg power in the long term may help reach a universal goal of healthy cognitive ageing.

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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4789972/

Perfekt ist das Modell Zwillingsstudie jedoch nicht, da selbst eineiige Zwillinge unterschiedliche Mutationen haben können: https://www.theguardian.com/science/2021...-study-suggests

Grundsätzlich eine gute Idee, aber man sollte doch einige Dinge im Hinterkopf behalten. Zwilingsstudien haben grundsätzliche methodologische Einwände:

1. Meistens sind die Teilnehmer in diesen Studien nicht zahlreich genug, um signifikante Schlussfolgerungen abzuleiten.
2. Adoptionsstudien haben das Problem, dass Kinder häufig in ähnliche Haushalte untergebracht werden.