ArTicle | AGEING NAILS |
Figure 1 Sagittal section through the distal phalanx showing the anatomical relations of the matrix and nail bed to the distal interphalangeal joint, the tendons and the bone. C=cuticle; ES=extendor tendon; FS=flexor tendon; HO=hyponychium; K=bone; L=lunula; M=matrix; NP=nail plate; PNW=proximal nail fold
life, though with a gradually decreasing speed. It does
not grey like the hair; however, in darker-skinned persons in whom nail pigmentation is physiologic, this will increase with age. It is not hormonally dependent and therefore does not show a cyclical growth characteristic (Table 1). The carbon–nitrogen ratio, which is indicative of
the keratin composition and therefore the ratio of alpha–amino acid and protein, increases with age. Women have a lower nitrogen–sulfur ratio compared with men, but the carbon content is the same. With ageing, the carbon content increases and the nitrogen content decreases, leading to a higher carbon–nitrogen ratio. The sulphur content and the nitrogen–sulphur ratio do not change. In women, the carbon content correlates with macronutrient intake, whereas nitrogen and sulfur contents show no relation to the diet (1). Nail calcium significantly decreases from the ages of 20–80 years (2). Calcium concentration is said to be lower in postmenopausal women as compared with premenopausal women (3). Differences in the structure and quality of the nails at an advanced age are mainly determined by age-dependent variations in lipid content of the nail plates (4). Lipoproteins are responsible for the ability of the nail to retain water. Low water content is
Figure 2 Mildly ridged thumb nail of a 45-year-old woman
associated with brittle nails. In winter, the water content is significantly lower, explaining why brittle nails are worse in winter (5). In women, but not in men, age correlates with internal cholesterol sulfate levels of nail plates (R=-0.59), independently of serum cholesterol or low-density lipoprotein (LDL) cholesterol variations. This age-dependent decrease in cholesterol sulphate levels might explain the higher incidence of brittle nails in women (6). With age, there is a gradual decrease of the nail growth
From the third to the ninth decade of life,
the slowdown in nail growth is approximately one third of the rate, decreasing from 0.1 mm/ day to 0.06 mm/day.
rate, a result of the diminished metabolic rate, decreased blood supply and less physical activity. From the third to the ninth decade of life, the slowdown in nail growth is approximately one third of the rate, decreasing from 0.1 mm/day to 0.06 mm/day. Individuals with peripheral circulatory disorders, as well as smokers, have an even more pronounced decrease in rates of growth. Most people will start to develop longitudinal
ridges in the nails during the fourth decade of life (Figure 2), which may also exhibit a beaded pattern with time. Individuals over the age of 60 years may
develop longitudinal splits in which the nail plate demonstrates more pronounced furrows at the undersurface, sometimes even associated with a V-shaped notch and circumscribed onycholysis (separation of the nail from the nail bed). This may be
Table 1 Physiologic differences in hair and nail Hair
Nail Cyclical growth
Androgen dependent Alopecia common
Graying of hair extremely common
Continuous life-long growth No hormonal dependency No alopecia-comparable loss
or growth disturbance
No graying; instead, often darkening in persons with racial nail pigmentation
60 ❚
Figure 3 Dull ridged nails with lamellar splitting of the free margin
(onychoschizia) in a 66-year-old woman
May 2011 |
prime-journal.com
IMAGE HANEKE
IMAGE HANEKE
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